NetApp NS0-158 - Questions & Answers

Verify that the LUN map contains four nodes by using the lun mapping show -fields reporting-nodes command.
Example cluster1::> lun mapping show -vserver SVM1 -volume vol1 -fields reporting-nodes vserver path igroup
reporting-nodes
-------- ----------- -------- --------------------------------------------- SVM1 /vol/vol1 ig1 cluster1-1,cluster1-2,cluster1- 3,cluster1-4 If the cluster contains only four nodes and all four are included as reporting-nodes, the reporting-nodes field displays a dash (-).
References:
https://library.netapp.com/ecm/ecm_download_file/ECMP12425790

ENOSPC is a UNIX operating system error that sometimes returns the message Not enough space is available to service your request." The error message occurs because of a shortage of file system space or lack of available media blocks.

You can delete Snapshot copies manually, or automatically by enabling the Snapshot autodelete capability for the volume.

Define and enable a policy for automatically deleting Snapshot copies by using the volume snapshot autodelete modify command.

You can use the snap delete command to delete a Snapshot copy before the preset interval to free disk space or because it is a manual Snapshot copy that is no longer needed but is not going to be automatically deleted.

Note: We get ENOSPC errors because Data ONTAP lets the Snapshot copy grow into the volume space.
Every write in WAFL is a write to a new block. If an old block is part of a Snapshot copy, Data ONTAP needs to preserve the old block and the new changed block. This is not a problem specific to NetApp.
Every storage vendor who supports a snapshot feature has to deal with it. There are two options when there is no space to accommodate the Snapshot copies:

References:
https://community.netapp.com/fukiw75442/attachments/fukiw75442/backup-and-restore-discussions/5980/1/tr-3633.pdf

Microsoft Multipath I/O (MPIO) is a Microsoft-provided framework that allows storage providers to develop multipath solutions that contain the hardware-specific information needed to optimize connectivity with their storage arrays. These modules are called device-specific modules (DSMs). The concepts around DSMs are discussed later in this document.
MPIO is protocol-independent and can be used with Fibre Channel, Internet SCSI (iSCSI), and Serial Attached SCSI (SAS) interfaces in Windows Server.

Asymmetric Logical Unit Access (ALUA), also known as Target Port Groups Support (TPGS), is a set of SCSI concepts and commands that define path prioritization for SCSI devices.

References:
https://kb.netapp.com/support/s/article/ka21A0000000d32QAA/asymmetric-logical-unit-access-alua-support-on-netapp-storage-frequently-asked-questions?language=en_US

B: To create an end-to-end relationship between SnapLock Compliance volumes by using SnapMirror, you need to create both the source and the destination volumes as SnapLock Compliance volumes and then initialize the mirroring relationship by using the snapmirror initialize command. The other commands you use differ depending on whether you are creating a volume SnapMirror relationship for a traditional volume or a FlexVol volume.

D: A SnapLock license entitles you to use both SnapLock Compliance mode and SnapLock Enterprise mode. SnapLock licenses are issued on a per-node basis. You must install a license for each node that hosts a SnapLock aggregate.

References:
https://library.netapp.com/ecmdocs/ECMP1196889/html/GUID-8ACE3CAB-
D338-4AFC-A530-0D0FEC3B9F94.html (https://library.netapp.com/ecm/ecm_download_file/ECMLP2507748)