Authentic Netapp Certification Exam NS0-155 Questions Answers

You must meet certain prerequisites before using SnapRestore:

- SnapRestore must be licensed on your storage system.

- There must be at least one Snapshot copy on the system that you can select to revert.

- The volume to be reverted must be online.

- The volume to be reverted must not be in use for data replication.

http://hd.kvsconsulting.us/netappdoc/733docs/html/ontap/onlinebk/GUID-A14081A3-9270-47EE-A1C1-EC52D3ABDBD0.html

https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_snapvault.1.html

The snapvault command has a number of subcommands. The set of subcommands differs on the primary and secondary.

On the primary, the subcommands allow users to configure and manage a set of snapshots for potential replication to the secondary, to abort replication transfers to the secondary, to check status, to restore data from the secondary, and to release resources when a primary qtree will no longer be replicated to a secondary.

On the secondary, the subcommands allow users to configure and manage the replication of primary paths to secondary qtrees, to configure and manage the snapshot schedules which control when all the qtrees in a secondary volume are updated from their respective primary paths and how many snapshots to save, to abort transfers, to check status, and to release resources preserved to restart backups from a restored qtree.

https://communities.netapp.com/servlet/JiveServlet/previewBody/4803-102-1-6405/tr-3548.pdf

It is important to remember that this is the case only when a complete site is lost. In the case of a failed controller at one of the sites, a normal cluster failover occurs. Due to the operation of SyncMirror, there is also added protection from multidrive or complete shelf failures. When a storage controller fails in an active-active configuration, the partner detects the failure and automatically (if enabled) performs a takeover of the dataserving responsibilities from the failed controller. Part of this process relies on the surviving controller being able to read information from the disks on the failed controller. If this quorum of disks is not available, then automatic takeover won’t be performed. In a MetroCluster configuration, manually executing a single command will allow a takeover to occur in spite of the lack of a quorum of disks. This "forced takeover" process breaks the mirrored relationships in order to bring the failed controller’s volumes on line.

forcetakeover -d is very dangerous. Not only can it cause data corruption, if not used carefully, it can also lead to a situation where both the node and its partner are operational (split brain). As such, it should only be used as a means of last resort when the takeover and forcetakeover commands are unsuccessful in achieving a takeover. The operator must ensure that the partner node does not become operational at any time while a node is in a takeover mode initiated by the use of this command. In conjunction with RAID mirroring, it can allow recovery from a disaster when the two nodes in the HA pair are located at two distant sites.