INTERVIEW Questions and Answers - Netapp Notes NCDA

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Netapp Hardware Interview Questions and Answers

1. How to improve the Netapp storage performance?
 
Ans:- 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 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 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.

2. Unable to map lun to solaris server, but solaris server side no issue. How to resolve the issue?

Ans:- FROM STORAGE SIDE:

    Verify iscsi/fcp license is added in storage
    Verify iscsi/fcp session is logged in from server side use below command 
Netapp> igroup show -v
    Verify luns are mapped to the corresponding igroup
    Verify whether correct host type is mentioned while creating igroup and lun
    Verify whether correct iqn/wwpn number is added to igroup
    Verify zoning is properly configured from switch side, if it is FCP protocol

3. How to create the LUN for linux server?

Ans:-    lun create –s size –t linux /vol/vol1/lunname
 
4. How to create qtree and provide the security?
 
Ans:-  
Netapp>qtree create /vol/vol1/qtreename 
Netapp>qtree security /vol/vol1/qtree unix|ntfs|mixed
5. How to copy volume filer to filer?

Ans:- ndmpcopy or snapmirror

6. How to resize the aggregate?

Ans:- 
Netapp> aggr add AggName no.of.disk

7. How to increase the volume?

Ans:- Traditional Volume


vol add VolName no.of.disk

Flexible Volume
 
vol size VolName +60g

8. What is qtree?
 
 Ans:-  qtree is Logical partition of the volume.

9. What is the default snap reserve in aggregate?
 
Ans:- 5%

10. What is snapshot?

Ans:-
A Snapshot copy is a read-only image of a traditional or FlexVol volume, or an aggregate, that captures the state of the file system at a point in time.
 
11. What are the raid groups Netapp supporting?, what is the difference between them?

Ans:-
Supported RAID types:

Raid-4

Raid-6 

Raid-Dp

12. What are the protocols you are using?
Ans:-
Say some protocols like NFS, CIFS, ISCSI and FCP
 
13. What is the difference between iscsi and fcp?
 
Ans:-
Iscsi-sending block through. iSCSI does not required dedicated network, it will work on existing network also. it work's an TCP/IP.
 
Fcp-send through fibre medium. Required an dedicated FC network.  Performance is so high compare to the iSCSI

14. What is the iscsi port number?
Ans:- 3260

15. 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

16. What is the difference between ONTAP 7 & 8?

In ONTAP 7 the individual aggregate is limited to 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.

17. What are the steps need to perform to configure SnapMirror?

The SnapMirror configuration process consists of the following four steps:
Refer Topic
Install the SnapMirror license on the source and destination systems: 
license add <code>
 
On the source, specify the host name or IP address of the SnapMirror destination systems you wish to authorize to replicate this source system.

options snapmirror.access host=dst_hostname1,dst_hostname2
 
For each source volume or qtree to replicate, perform an initial baseline transfer. For volume SnapMirror

restrict the destination volume first: vol restrict dst_vol

Then initialize the volume SnapMirror baseline, using the following syntax on the destination:

snapmirror initialize -S src_hostname:src_v

oldst_hostname:dst_vol

For a qtree SnapMirror baseline transfer, use the following syntax on the destination:

snapmirror initialize –S src_hostname:/vol/src_vol/src_qtree

dst_hostname:/vol/dst_vol/dst_qtree


18. While doing baseline transfer you’re getting error message. What are the troubleshooting steps you’ll do?

Ans:-
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

19. Explain the different types of replication modes..?

The 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.

20. How do you configure multiple path in Snapmirror?

Add a connection name line in the snapmirror.conf file
/etc/snapmirror.conf
FAS1_conf = multi (FAS1-e0a,FAS2-e0a) (FAS1-e0b,FAS2-e0b)

21. Explain how De-Duplication 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 De-duplication feature works well with datasets that have lots of duplicated date (for example, full backups).

22. What is the command used to see amount of space saved using De-duplication?

df –s <volume name>

23. Command used to check progress and status of De-duplication?

sis status
 
24. How do you setup 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

25. What is metadata?

Metadata is defined as data providing information about one or more aspects of the data,

1. Inode file
2. Used block bitmap file
3. Free block bitmap file
 
26. How do you shutdown filer through RLM?
 
ssh “rlm ip address”
RLM_Netapp> system power on

27. After creating LUN (iSCSI) & mapped the LUN to particular igroup, the client not able to access the LUN. What are the trouble shooting 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

28. In CIFS how do you check who is using most?
 
cifs top

29. How to check cifs performance statistics.?

cifs stat

30. 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.

31. what is degraded mode? If you don't have parity for failed disks then?

If the spare disk is not added within 24hours,then filer will be shutdown automatically to avoid further disk failures and data loss.

32. Did you ever do ontap upgrade? From which version to which version and for what reason?

Yes i have done ontap upgrade from version 7.2.6.1 to 7.3.3 due to lot of bugs in old version.

33. How do you create a lun ?

lun create -s <lunsize> -t <host type> <lunpath>


34. 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

35. 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


36. What is the diff bet cf takeover and cf force takeover?

If partner shelf power is off, if you try to takeover it will not take. if you do as force using (-f) it will work

37. What is LIF.?

LIF ( Logical interface) :
As the name suggest its a logical interface which is created from physical interface of NetApp controllers.

38. What is VServer..?

A Vserver is defined as logical container which holds the volumes. A 7 mode vfiler is called as a vserver in Clustered mode .  

39. What is junction path..? 

 This is a new term in cluster mode and this is used for mounting.Volume junctions are a way to join individual volumes together into a single, logical namespace to enable data access to NAS clients.

40. What is infinite volumes..?

NetApp Infinite Volume is a software abstraction hosted over clustered Data ONTAP

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