Top 50+ NetApp Interview Questions & Answers [SUCCESS 95%]
Last updated on 08th Jun 2020, Blog, Interview Questions
NetApp, formerly Network Appliance Inc., is a company in the computer technologies industry specializing in data storage hardware and associated management software. NetApp storage equipment is used by enterprises and service providers to store and to share large amounts of digital data across physical and hybrid cloud environments.
1. What is QTree?
A qtree is different from the traditional directory on a UNIX system in many ways including:
- A qtree can be assigned a security style. We can create a qtree with UNIX, NT or mixed security style.
- CIFS oplocks can be enabled on the qtree. CIFS oplocks help the client to buffer data locally, performing read ahead from an open file. The nature of buffering depends on the nature of oplocks granted.
- We can set disk space & file limits at qtree level, allowing control over resource allocation to multiple projects.
- Say we have 3 departments, finance, HR, sales and each function has separate qtree’s. We can then assign 20 GB to sales, 100 GB to HR, since it contains training videos etc. and 75 GB to finance.
2. What is the difference between Traditional volume and Flex volume..?
Volume important stuff:
- The name of the volume
- The size of the volume
- A security style, which determines whether a volume can contain files that use UNIX security, files that use NT file system (NTFS) file security, or both types of files
- Whether the volume uses CIFS oplocks (opportunistic locks)
- The type of language supported
- The level of space guarantees (for FlexVol volumes only)
- Disk space and file limits (quotas)
- A snapshot schedule
- Whether the volume is designated as a SnapLock™ volume
- Whether the volume is a root.
- The smallest possible 2 disk raid 4 3 disk raid dp
- A traditional volume is contained by a single, dedicated, aggregate.
- The only way to increase the size of a traditional volume is to add entire disks to its containing aggregate it is impossible to decrease the size of a traditional volume.
Flexible volume (FlexVol):
- Because the volume is managed separately from the aggregate,
- FlexVol volumes give you a lot more options for managing the size of the volume.
- You can create FlexVol volumes in an aggregate nearly instantaneously.
- They can be as small as 20 MB and as large as the volume capacity that is supported for your storage system You can increase and decrease the size of a FlexVol in small increments (as small as 4 KB), nearly instantaneously
3. Difference between Volume SnapMirror and Qtree Snapmirror..?
|Volume SnapMirror||Qtree SnapMirror|
|Synchronous or asynchronous replication is supported for volumes.||Only asynchronous replication is supported for qtrees.|
|Destination volume is read-only.||Destination qtree is read-only. However, the volume on which the qtree is located must be online and writable.|
|Source and destination volumes must both be either traditional volumes or FlexVol volumes.||Source and destination qtrees can be on any type of volumes, traditional volumes or FlexVol volumes.|
|Replicates Snapshot copies of a source volume and all its qtrees, to the destination volume||Replicates only the contents of an individual qtree to a destination|
|You need to set a destination volume to restricted, read-only status,
before setting it up for replication.
|The destination volume for qtree replication is writable, and must not be read-only.|
|Replication of a volume on the destination takes up the space allocated to the source volume, irrespective of how much of the volume is used for storing data.||If you need to mirror only the data stored on an individual qtree, then SnapMirror replication of that individual qtree uses slightly more disk space and directories on the destination qtree than the source qtree.|
|Replication can be set up to a destination volume from only one source volume. This implies that one destination volume cannot be used for replicating multiple source volumes.||Replication can be set up for a maximum of 255 qtrees on any one volume.|
|Block-for-block replication||Logical replication|
|It transfers the file system verbatim. Therefore, older releases of Data ONTAP cannot understand file system transfers from a later release of Data ONTAP.||All the files and directories in the source file system are created in the destination file system. Therefore, you can replicate data between astorage system running an older version of Data ONTAP and a storage system running a newer version.|
Note: If the source file system contains a file type that cannot be represented on the destination file system, the replication will fail. For example, Data ONTAP 7.0 supports files up to 16 TB in size, whereas earlier versions of Data ONTAP support files up to 4 TB. If the source system is running Data ONTAP 7.0, the qtree you want to replicate contains a file greater than 4 TB, and the destination system is running an earlier version of Data ONTAP, the replication will fail.
4. Difference between Hard Zoning and Soft Zoning..?
Here’s what I thought was correct:
- Hard zoning is done by the switches, disallowing certain WWNs (or ports) from talking by examining source and destination information, regardless of knowledge of one another’s existence. I compare this to conventional IP firewalls (only certain IPs can talk to one another – I know Google’s IP but I still cannot reach it).
- Soft zoning allows everything to reach everything else, but prevents discovery of everything in the fabric by limiting what information the name server will respond with when a new HBA wants to know what it can talk to. I compare this to a DNS server that provides different responses based on the querying host – hosts can still talk if they know one another’s IP address.
- WWN and port-based zoning are unrelated to the above – they simply imply how you identify members of a zone.
5. How to Create Traditional Volume..?
- Aggr status -v
(Optional) Determine the free disk resources on your filer by entering the following command:
- aggr status -s
3 To create a traditional volume, enter the following command:
- aggr create trad_vol -v ndisks[@disksize]
- aggr create new_tvol -v 16@72g
4 (Optional) To verify the creation of the traditional volume named:
new_tvol, enter the following command:
- vol status new_tvol -v 16@72
- All volumes, including traditional volumes, must be uniquely named within the same filer.
- you can create a maximum of 100 traditional volumes within one storage system.
- Minimum traditional volume size depends on the disk capacity and RAID protection level
6. Define the SAN Switch Ports..?
|N-port||network port or node port||Node port used to connect a node to a Fibre Channel switch|
|F-port||fabric port||Switch port used to connect the Fibre Channel fabric to a node|
|L-port||loop port||Node port used to connect a node to a Fibre Channel loop|
|NL-port||network + loop port||Node port which connects to both loops and switches|
|FL-port||fabric + loop port||Switch port which connects to both loops and switches|
|E-port||extender port||Used to cascade Fibre Channel switches together|
|G-port||general port||General purpose port which can be configured to emulate other port types|
|EX_port||external port||Connection between a fibre channel router and a fibre channel switch; on the switch side, it looks like a normal E_port — but on the router side, it is a EX_port|
7. Can you describe SAND in your own word?
A storage area network (SAN) is a high-speed special-purpose network (or subnetwork) that interconnects different kinds of data storage devices with associated data servers on behalf of a larger network of users. Typically, a storage area network is part of the overall network of computing resources for an enterprise. A storage area network is usually clustered in close proximity to other computing resources such as IBM Power5 boxes but may also extend to remote locations for backup and archival storage, using wide area network carrier technologies such as ATM or SONET .
A storage area network can use existing communication technology such as IBM’s optical fiber ESCON or it may use the newer Fibre Channel technology. Some SAN system integrators liken it to the common storage bus (flow of data) in a personal computer that is shared by different kinds of storage devices such as a hard disk or a CD-ROM player.
SANs support disk mirroring, backup and restore, archival and retrieval of archived data, data migration from one storage device to another, and the sharing of data among different servers in a network. SANs can incorporate subnetworks with network-attached storage (NAS) systems.
8. So you mention NAS, but What is NAS?
Network-attached storage (NAS) is hard disk storage that is set up with its own network address rather than being attached to the department computer that is serving applications to a network’s workstation users. By removing storage access and its management from the department server, both application programming and files can be served faster because they are not competing for the same processor resources. The network-attached storage device is attached to a local area network (typically, an Ethernet network) and assigned an IP address. File requests are mapped by the main server to the NAS file server.
Network-attached storage consists of hard disk storage, including multi-disk RAID systems, and software for configuring and mapping file locations to the network-attached device. Network-attached storage can be a step toward and included as part of a more sophisticated storage system known as a storage area network (SAN).
NAS software can usually handle a number of network protocols, including Microsoft’s Internetwork Packet Exchange and NetBEUI, Novell’s Netware Internetwork Packet Exchange, and Sun Microsystems’ Network File System. Configuration, including the setting of user access priorities, is usually possible using a Web browser.
9. What is SMTP and how it works?
SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol used in sending and receiving e-mail. However, since it is limited in its ability to queue messages at the receiving end, it is usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server. In other words, users typically use a program that uses SMTP for sending e-mail and either POP3 or IMAP for receiving email. On Unix-based systems, sendmail is the most widely-used SMTP server for email. A commercial package, Sendmail, includes a POP3 server. Microsoft Exchange includes an SMTP server and can also be set up to include POP3 support.
10. Do you have any idea about NAT?
Short for Network Address Translation, an Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations.
NAT serves three main purposes:
- Provides a type of firewall by hiding internal IP addresses
- Enables a company to use more internal IP addresses. Since they’re used internally only, there’s no possibility of conflict with IP addresses used by other companies and organizations.
- Allows a company to combine multiple ISDN connections into a single Internet connection.
Dynamic addressing simplifies network administration because the software keeps track of IP addresses rather than requiring an administrator to manage the task. This means that a new computer can be added to a network without the hassle of manually assigning it a unique IP address. Many ISPs use dynamic IP addressing for dial-up users.
11. What does SNMP stand for?
Short for Simple Network Management Protocol, a set of protocols for managing complex networks. SNMP works by sending messages, called Protocol Data Units, to different parts of a network. SNMP-compliant devices, called Agents, store data about themselves in Management Information Bases and return this data to the SNMP requesters.
12. What do you know about TCPDump?
TCPdump is a common computer network debugging tool that runs under the command line. It allows the user to intercept and display TCP/IP and other packets being transmitted or received over a network to which the computer is attached. Tcpdump works on most Unix-like platforms: Linux, Solaris, BSD, Mac OS X, HP-UX and AIX among others. On Windows, WinDump can be used; it’s a port of tcpdump to Windows.
You must have a root or superuser authority to use TCPdump in a UNIX -like environment.
13. What do software RAID Levels do?
Redundant Arrays of Independent Disks (RAID) is formally defined as a method to store data on any type of disk medium.
LDAP: The Light Directory Access Protocol (LDAP) defines a standard method for accessing and updating information in a directory (a database) either locally or remotely in a client-server model.
14. What are the benefits of fibre channel SANs?
Fibre Channel SANs are the de facto standard for storage networking in the corporate data center because they provide exceptional reliability, scalability, consolidation, and performance. Fibre Channel SANs provide significant advantages over direct-attached storage through improved storage utilization, higher data availability, reduced management costs, and highly scalable capacity and performance.
15. What environment is most suitable for fibre channel SANs?
Typically, Fibre Channel SANs are most suitable for large data centers running business-critical data, as well as applications that require high-bandwidth performance such as medical imaging, streaming media, and large databases. Fibre Channel SAN solutions can easily scale to meet the most demanding performance and availability requirements.
16. What customer problems do fibre channel SANs solve?
The increased performance of Fibre Channel enables a highly effective backup and recovery approach, including LAN-free and server-free backup models. The result is a faster, more scalable, and more reliable backup and recovery solution. By providing flexible connectivity options and resource sharing, Fibre Channel SANs also greatly reduce the number of physical devices and disparate systems that must be purchased and managed, which can dramatically lower capital expenditures. Heterogeneous SAN management provides a single point of control for all devices on the SAN, lowering costs and freeing personnel to do other tasks.
17. How long has the fibre channel been around?
Development started in 1988, ANSI standard approval occurred in 1994, and large deployments began in 1998. Fibre Channel is a mature, safe, and widely deployed solution for high-speed (1 GB, 2 GB, 4 GB) communications and is the foundation for the majority of SAN installations throughout the world.
18. What is the future of fibre channel SANs?
Fibre Channel is a well-established, widely deployed technology with a proven track record and a very large installed base, particularly in high-performance, business-critical data center environments. Fibre Channel SANs continue to grow and will be enhanced for a long time to come. The reduced costs of Fibre Channel components, the availability of SAN kits, and the next generation of Fibre Channel (4 GB) are helping to fuel that growth. In addition, the Fibre Channel roadmap includes plans to double performance every three years.
19. What are the benefits of a 4gb fibre channel?
Benefits include twice the performance with little or no price increase, investment protection with backward compatibility to 2 GB, higher reliability due to fewer SAN components (switch and HBA ports) required, and the ability to replicate, back up, and restore data more quickly. 4 GB Fibre Channel systems are ideally suited for applications that need to quickly transfer large amounts of data such as remote replication across a SAN, streaming video on demand, modeling and rendering, and large databases. 4 GB technology is shipping today.
20. How is the fibre channel different from ISCSI?
Fibre Channel and iSCSI each have a distinct place in the IT infrastructure as SAN alternatives to DAS. Fibre Channel generally provides high performance and high availability for business-critical applications, usually in the corporate data center. In contrast, iSCSI is generally used to provide SANs for business applications in smaller regional or departmental data centers.
21. When should I deploy a fibre channel instead of ISCSI?
For environments consisting of high-end servers that require high bandwidth or data center environments with business-critical data, Fibre Channel is a better fit than iSCSI. For environments consisting of many midrange or low-end servers, an IP SAN solution often delivers the most appropriate price/performance.
22. Name some of the SAN topologies ?
Point-to-point, arbitrated loop, and switched fabric topologies.
23. What are the advantages of RAID?
Redundant Array of Inexpensive Disks:
- Depending on how we configure the array, we can have the
- data mirrored [RAID 1] (duplicate copies on separate drives)
- striped [RAID 0] (interleaved across several drives), or
- parity protected [RAID 5](extra data written to identify errors).
- These can be used in combination to deliver the balance of performance and reliability that the user requires.
24. Define RAID? Which one do you feel is a good choice?
RAID (Redundant array of Independent Disks) is a technology to achieve redundancy with faster I/O. There are Many Levels of RAID to meet different needs of the customer which are: R0, R1, R3, R4, R5, R10, R6.
Generally customers choose R5 to achieve better redundancy and speed and it is cost effective.
- R0 – Striped set without parity/[Non-Redundant Array]: Provides improved performance and additional storage but no fault tolerance. Any disk failure destroys the array, which becomes more likely with more disks in the array. A single disk failure destroys the entire array because when data is written to a RAID 0 drive, the data is broken into fragments. The number of fragments is dictated by the number of disks in the drive. The fragments are written to their respective disks simultaneously on the same sector. This allows smaller sections of the entire chunk of data to be read off the drive in parallel, giving this type of arrangement huge bandwidth. RAID 0 does not implement error checking so any error is unrecoverable. More disks in the array means higher bandwidth, but greater risk of data loss
- R1 – Mirrored set without parity: Provides fault tolerance from disk errors and failure of all but one of the drives. Increased read performance occurs when using a multi-threaded operating system that supports split seeks, very small performance reduction when writing. Array continues to operate so long as at least one drive is functioning. Using RAID 1 with a separate controller for each disk is sometimes called duplexing.
- R3 – Striped set with dedicated parity/Bit interleaved parity: This mechanism provides an improved performance and fault tolerance similar to RAID 5, but with a dedicated parity disk rather than rotated parity stripes. The single parity disk is a bottle-neck for writing since every write requires updating the parity data. One minor benefit is the dedicated parity disk allows the parity drive to fail and operation will continue without parity or performance penalty.
- R4 – Block level parity: Identical to RAID 3, but does block-level striping instead of byte-level striping. In this setup, files can be distributed between multiple disks. Each disk operates independently which allows I/O requests to be performed in parallel, though data transfer speeds can suffer due to the type of parity. The error detection is achieved through dedicated parity and is stored in a separate, single disk unit.
- R5 – Striped set with distributed parity: Distributed parity requires all drives but one to be present to operate; drive failure requires replacement, but the array is not destroyed by a single drive failure. Upon drive failure, any subsequent reads can be calculated from the distributed parity such that the drive failure is masked from the end user. The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive.
- R6 – Striped set with dual distributed Parity: Provides fault tolerance from two drive failures; array continues to operate with up to two failed drives. This makes larger RAID groups more practical, especially for high availability systems. This becomes increasingly important because large-capacity drives lengthen the time needed to recover from the failure of a single drive. Single parity RAID levels are vulnerable to data loss until the failed drive is rebuilt: the larger the drive, the longer the rebuild will take. Dual parity gives time to rebuild the array without the data being at risk if one drive, but no more, fails before the rebuild is complete.
25. What is the difference between RAID 0+1 and RAID 1+0?
- RAID 0+1 (Mirrored Stripped): In this RAID level all the data is saved on striped volumes which are in turn mirrored, so any disk failure saves the data loss but it makes the whole stripe unavailable. The key difference from RAID 1+0 is that RAID 0+1 creates a second striped set to mirror a primary striped set. The array continues to operate with one or more drives failed in the same mirror set, but if drives fail on both sides of the mirror the data on the RAID system is lost. In this RAID level if one disk is failed full mirror is marked as inactive and data is saved only one striped volume.
- RAID 1+0 (Striped Mirrored): In this RAID level all the data is saved on mirrored volumes which are in turn stripped, so any disk failure saves data loss. The key difference from RAID 0+1 is that RAID 1+0 creates a striped set from a series of mirrored drives. In a failed disk situation RAID 1+0 performs better because all the remaining disks continue to be used. The array can sustain multiple drive losses so long as no mirror loses both its drives. This RAID level is most preferred for high performance and high data protection because rebuilding of RAID 1+0 is less time consuming in comparison to RAID 0+1.
26. When JBOD’s are used?
“Just a Bunch of Disks”: It is a collection of disks that share a common connection to the server, but don’t include the mirroring, striping, or parity facilities that RAID systems do, but these capabilities are available with host-based software.
27. Differentiate RAID & JBOD?
- RAID(Redundant Array of Inexpensive Disks): Fault-tolerant grouping of disks that server sees as a single disk volume Combination of parity-checking, mirroring, striping Self-contained, manageable unit of storage
- JBOD(Just a Bunch of Disks): Drives independently attached to the I/O channel Scalable, but requires server to manage multiple volumes . Do not provide protection in case of drive failure
28. What is a HBA?
Host bus adapters (HBAs) are needed to connect the server (host) to the storage.
29. What are the advantages of SAN?
- Massively extended scalability.
- Greatly enhanced device connectivity.
- Storage consolidation.
- LAN-free backup.
- Server-less (active-fabric) backup.
- Server clustering.
- Heterogeneous data sharing.
- Disaster recovery
- Remote mirroring.
While answering people do NOT portray clearly what they mean & what advantages each of them have, which are cost effective & which are to be used for the client’s requirements.
30. What is the difference b/w SAN and NAS?
The basic difference between SAN and NAS, SAN is Fabric based and NAS is Ethernet based.
- SAN(Storage Area Network): It accesses data on block level and produces space to host in the form of a disk.
- NAS(Network attached Storage): It accesses data on file level and produces space to host in the form of a shared network folder.
31. Can you briefly explain each of these Storage area components?
Fabric Switch: It’s a device which interconnects multiple network devices .There are switches starting from 16 port to 32 ports which connect 16 or 32 machine nodes etc. vendors who manufacture these kinds of switches are Brocade, McData.
32. What is the most critical component in SAN?
Each component has its own criticality with respect to business needs of a company.
33. How is a SAN managed?
There are many management software’s used for managing SAN’s to name a few:
- IBM Tivoli Storage Manager.
- CA Unicenter.
- Veritas Volume Manager.
34. What is the highest and lowest priority of SCSI?
There are 16 different ID’s which can be assigned to SCSI device 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8.
Highest priority of SCSI is ID 7 and lowest ID is 8.
35. What is Array?
Array is a group of Independent physical disks to configure any Volumes or RAID volumes.
36. Can you describe at-least 3 troubleshooting scenarios which you have come across in detail?
36A. SCENARIO 1: How do you find/debug when there is error while working SCSI devices?
In our daily SAN troubleshooting there are many management and configuration tools we use to see when there is a failure with target device or initiator device.
Sometimes it is even hard to troubleshoot some of the things such as media errors in the drives, or some of the drives taking a long time to spin-up. In such cases these utilities will not come to help. To debug this kind of information most of the controller will be implemented with a 3-pin serial debug port. With serial port debug connector cable you can collect the debug information with hyper terminal software.
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36B. SCENARIO 2: I am having an issue with a controller. It’s taking a lot of time to boot and detect all the drives connected. How can I solve this.?
There are many possibilities that might cause this problem. One of the reasons might be you are using bad drives that cannot be repaired. In those cases you replace the disks with working ones.
Another reason might be slots you connected your controller to a slot which might not be supported. Try to connect with other types of slots. One more probable reason is if you have flashed the firmware for different OEM’s on the same hardware. To get rid of this the flash utilities will be having the option to erase all the previous and EEPROM and boot block entry options. Use that option to rectify the problem.
36C. SCENARIO 3: I am using tape drive series 700X, even the vendor information on the Tape drive says 700X, but the POST information while booting the server is showing as 500X what could be the problem?
First you should make sure your hardware is of which series, you can find out this in the product website. Generally you can see this because in most of the testing companies they use the same hardware to test different series of the same hardware type. What they do is they flash the different series firmware. You can always flash back to the exact hardware type.
37. Which are the 4 types of SAN architecture types ?
38. Which command is used in linux to know the driver version of any hardware device?
39. How many minimum drives are required to create R5 (RAID 5)?
You need to have at least 3 disk drives to create R5.
40. Can you name some of the states of the RAID array?
There are states of RAID arrays that represent the status of the RAID arrays which are given below:
41. What are the protocols used in the physical/data link and network layer of SAN?
- Fibre Channel.
42. What is storage virtualization?
Storage virtualization is amalgamation of multiple n/w storage devices into a single storage unit.
43. Describe in brief the composition of FC Frame?
- Start of the Frame locator
- Frame header (includes destination id and source id, 24 bytes/6 words).
- Data Payload (encapsulate SCSI instruction can be 0-2112 bytes in length).
- CRC (error checking, 4 bytes).
- End of Frame (1 byte).
44. What is virtualization?
Virtualization is logical representation of physical devices. It is the technique of managing and presenting storage devices and resources functionally, regardless of their physical layout or location. Virtualization is the pooling of physical storage from multiple network storage devices into what appears to be a single storage device that is managed from a central console. Storage virtualization is commonly used in a storage area network (SAN). The management of storage devices can be tedious and time-consuming. Storage virtualization helps the storage administrator perform the tasks of backup, archiving, and recovery more easily, and in less time, by disguising the actual complexity of the SAN.
45. What is HA?
HA High Availability is a technology to achieve failover with very less latency. It’s a practical requirement of data centers these days when customers expect the servers to be running 24 hours on all 7 days around the whole 365 days a year – usually referred as 24x7x365. So to achieve this, a redundant infrastructure is created to make sure if one database server or if one app server fails there is a replica Database or Appserver ready to take-over the operations. End customers never experience any outage when there is a HA network infrastructure.
46. Can you name some of the available tape media types?
There are many types of tape media available to back up the data, some of them are:
- DLT: Digital Linear Tape technology for tape backup/archive of networks and servers; DLT technology addresses mid range to high-end tape backup requirements.
- LTO: Linear Tape Open a new standard tape format developed by HP, IBM, and Se agate.
- AIT: Advanced Intelligent Tape a helical scan technology developed by Sony for tape backup/archive of networks and servers, specifically addressing mid range to high-end backup requirements.
47. Can we assign a hot spare to R0 (RAID 0) array?
No, since R0 is not a redundant array, failure of any disks results in failure of the entire array so we cannot rebuild the hot spare for the R0 array.
48. Name the features of SCSI-3 standard?
- QAS: Quick arbitration and selection.
- Domain Validation.
- CRC: Cyclic redundancy check.
49. What is Multipath I/O?
Fault tolerant technique where there is more than one physical path between the CPU in the computer systems and its main storage devices through the buses, controllers, switches and other bridge devices connecting them.
50. What is a disk array?
Set of high performance storage disks that can store several terabytes of data. Single disk array can support multiple points of connection to the network.
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51. What are different types of protocols used in transportation and session layers of SAN?
- Fibre Channel Protocol (FCP).
- Internet SCSI (iSCSI).
- Fibre Channel IP (FCIP).
52. What is the type of Encoding used in Fibre Channel?
8b/10b, as the encoding technique is able to detect all most all the bit errors
53. What are the main constraints of SCSI in storage networking?
- Deployment distance (max. of 25 mts).
- Number of devices that can be interconnected (16).
54. What is a Fabric?
Interconnection of Fibre Channel Switches.
55. What are the services provided by Fabric to all the nodes?
- Fabric Login.
- Fabric Address Notification.
- Registered state change notification.
- Broadcast Servers.
56. What is the difference between LUN and WWN?
- LUN: Unique number that is assigned to each storage device or partition of the storage that the storage can support.
- WWN: 64bit address that is hard coded into a fibre channel HBA and this is used to identify individual ports (N_Port or F_Port) in the fabric.
57. What are the different topologies in Fibre Channel?
- Arbitrary Loop.
- Switched Fabric Loop.
58. What are the layers of Fibre Channel Protocol?
- FC Physical Media.
- FC Encoder and Decoder.
- FC Framing and Flow control.
- FC Common Services.
- FC Upper Level Protocol Mapping.
59. What is zoning?
Fabric management service that can be used to create logical subsets of devices within a SAN. This enables portioning of resources for management and access control purposes.
60. What is the purpose of a disk array?
Probability of unavailability of data stored on the disk array due to single point failure is totally eliminated.
61. How does FC Switch maintain the addresses?
FC Switch uses a simple name server (SNS) to maintain the mapping table.
62. What are the two major classification of zoning?
Two types of zoning are:
- Software Zoning.
- Hardware Zoning.
63. What are different levels of zoning?
- Port Level zoning.
- WWN Level zoning.
- Device Level zoning.
- Protocol Level zoning.
- LUN Level zoning.
64. What are the 3 prominent characteristics of SAS Protocol?
- Native Command Queuing (NCQ.)
- Port Multiplier.
- Port Selector.
65. What are the 5 states of Arbitrary Loop in FC?
- Loop Initialization.
- Loop Monitoring.
- Loop arbitration.
- Open Loop.
- Close Loop.
66. What is LUN Masking?
A method used to create an exclusive storage area and access control. And this can be achieved by a storage device control program.
67. What is a snapshot?
A snapshot of data object contains an image of data at a particular point of time.
68. What is hot-swapping?
Devices are allowed to be removed and inserted into a system without turning off the system.
69. How To Improve The Netapp Storage Performance?
There is no direct answer for this question but we shall do it in several way:
- If volume/lun present in ATA/SATA harddisk aggregate, then the volume can be migrated to FC/SAS disk aggregate. Either you can use flash cache to improve performance.
- For NFS/CIFS instead of accessing from a single interface, multi mode vif can be configured to get better bandwidth and fault tolerance.
- Always advised to keep aggr/vol utilization below 90%.
- Avoid doing multiple volume backup in a single point of time.
- Aggr/volume/lun reallocation can be done to re–distribute the data to multiple disk for better striping performance.
- Schedule scrubbing and De-duplication scanning after business hours.
- Create multiple loops and connect different types of shelf’s to each loop
- Avoid mixing up different speeds of disk and different types of disk in a same aggregate.
- Always keep sufficient spare disk to replace in case of disk failure. Because reconstruction time will take more time and cause negative performance.
- Keep the advised version of firmware/software which is recommended by Netapp.
70. Unable To Map Lun To Solaris Server, But Solaris Server Side No Issue. How To Resolve The Issue?
From Storage side :
- Verify iscsi/fcp license is added in storage
- Verify iscsi/fcp session is logged in from server side use command Netapp> igroup show -v
- Verify luns are mapped to the corresponding igroup
- Verify whether correct host type is mentioned while creating group and lun
- Verify whether correct iqn/wwn number is added to igroup
- Verify zoning is properly configured from switch side, if it is FCP protocol
71. How To Create The Lun For Linux Server?
- lun create –s size –t linux /vol/vol1/lunname
72. How To Create Qtree And Provide The Security?
- Netapp>qtree create /vol/vol1/qtreename
- Netapp>qtree security /vol/vol1/qtree unix|ntfs|mixed
73. How To Copy Volume Filer To Filer?
- ndmpcopy or snapmirror
74. How To Resize The Aggregate?
- Netapp> aggr add TagName no.of.disk
75. How To Increase The Volume?
- Traditional Volume: vol add VolName no.of.disk
- Flexible Volume: vol size VolName +60g
76. What Is Qtree?
qtree is Logical partition of the volume.
77. What Are The Raid Groups Netapp Supporting?, What Is The Difference Between Them?
Supported RAID types:
78. What Are The Protocols You Are Using?
Say some protocols like NFS, CIFS, ISCSI and FCP
79. What Is The Difference Between Iscsi And Fcp?
- Iscsi-sending block through. iSCSI does not require a dedicated network, it will work on existing networks also. It works on TCP/IP.
- Fcp-send through fibre medium. Required an dedicated FC network. Performance is so high compare to the iSCSI
80. What Is The Difference Between Ndmp Copy And Vol Copy?
- Ndmp copy: network data management protocol(used for tape backup)
- Vol copy: is used to transfer volume to same or another aggregate
81. What Is The Difference Between Ontap 7 & 8?
In ONTAP 7 the individual aggregate is limited to a maximum of 16 TB. Where ONTAP 8 supports the new 64 bit aggregate and hence the size of the individual aggregate extends to 100 TB.
82. While Doing Baseline Transfer You’re Getting an Error Message. What Are The Troubleshooting Steps You’ll Do?
- Check both the hosts are reachable by running “ping” command
- Check whether the TCP port 10566 & 10565 are open from firewall
- Check whether the snapmirror license are installed in both filers
83. Explain The Different Types Of Replication Modes..?
SnapMirror Async mode replicates Snapshot copies from a source volume or qtree to a destination. It will support to replicate more than 800Kms Long. volume or qtree. Incremental updates are based on a schedule or are performed manually using the snapmirror update command. Async mode works with both volume SnapMirror and qtree SnapMirror.
SnapMirror Sync mode replicates writes from a source volume to a destination volume at the same time it is written to the source volume. SnapMirror Sync is used in environments that have zero tolerance for data loss. it will note support more then 300Kms long. SnapMirror Semi-Sync provides a middle-ground solution that keeps the source and destination systems more closely synchronized than Async mode, but with less impact on performance.
84. How Do You Configure Multiple Paths In Snapmirror?
Add a connection name line in the snapmirror.conf file:
- FAS1_conf = multi (FAS1-e0a,FAS2-e0a) (FAS1-e0b,FAS2-e0b)
85. Explain How Deduplication Works?
In the context of disk storage, De-duplication refers to any algorithm that searches for duplicate data objects (for example, blocks, chunks, files) and discards those duplicates. When duplicate data is detected, it is not retained, but instead a “data pointer” is modified so that the storage system references an exact copy of the data object already stored on disk. This Deduplication feature works well with datasets that have lots of duplicated data (for example, full backups).
86. What Is The Command Used To See Amount Of Space Saved Using Deduplication?
- df –s <volume name>
87. Command Used To Check Progress And Status Of De-duplication?
- sis status
88. How Do You Setup a Snapvault Snapshot Schedule?
- pri> snapvault snap sched vol1 sv_hourly 22@0-22:
- This schedule is for the home directories volume vol1
- Creates hourly Snapshot copies, except 11:00 p.m.
- Keeps nearly a full day of hourly copies
89. What Is Metadata?
Metadata is defined as data providing information about one or more aspects of the data.
- Inode file
- Used block bitmap file
- Free block bitmap file
90. How Do You Shutdown Filer Through Rlm?
- ssh “rlm ip address”
- RLM_Netapp> system power on
91. After Creating Lun (iscsi) & Mapped The Lun To Particular Igroup, The Client Not Able To Access The Lun. What Are The Troubleshooting Steps You Take?
- Check whether IQN number specified is correct
- Check whether the created LUN is in “restrict” mode
- Check the iscsi status
- Un-map and map the LUN once again
- Check Network connectivity communication
92. In Cifs How Do You Check Who Is Using Most?
- cifs top
93. What Do You Do If A Customer Reports A Particular Cifs Share Is Responding Slow?
- Check the r/w using “cifs stat” & “sysstat -x 1”.
- If disk & cpu utilization is more then problem is with filer side only.
- CPU utilization will be high if more disk r/w time, i.e.,during tape backup & also during scrub activities.
94. What Is Degraded Mode? If You Don’t Have Parity For Failed Disks Then?
If the spare disk is not added within 24hours,then the filer will be shut down automatically to avoid further disk failures and data loss.
95. Did You Ever Do Ontap Upgrade? From Which Version To Which Version And For What Reason?
Yes i have done ontap upgrade from version 188.8.131.52 to 7.3.3 due to a lot of bugs in the old version.
96. How Do You Monitor The Filers?
Using DFM(Data Fabric Manager) or also using SNMP you can monitor the filer. Using any monitoring systems like .i.e.Nagios
97. What Are The Prerequisites For A Cluster?
Cluster interconnect cable should be connected:
- shelf connect should be properly done for both the controllers with Path1 and Path2
- cluster license should be enabled on both the nodes
- Interfaces should be properly configured for fail over
- cluster should be enabled
98. What Is The Diff Bet Cf Takeover And Cf Force Takeover?
If partner shelf power is off, if you try to take over it will not take. if you do as force using (-f) it will work
99. What Is Lif.?
LIF ( Logical interface) : As the name suggests its a logical interface which is created from the physical interface of NetApp controllers.
100. What Is Vserver..?
A Vserver is defined as a logical container which holds the volumes. A 7 mode vfiler is called as a vserver in Clustered mode .