High Availability

Data protection – NetApp way

When I say data protection I mean the features to back up data and to be able to recover it when needed. Basically you need to back up data for the following reasons:

  • to protect data from accidentally deleted files, application crashers, viruses, data corruption etc.
  • to archive data for future use or for legal purposes
  • to recover from a distaster

NetApp developed many methods of protecting data. To use some of them you need an extra licence, some of them are the standards features of Data ONTAP.

 aggr copy

aggr copy gives up fast block copy of data stored in aggregates. Just a quick remain, all data served by NetApp are located on the aggr. With the aggr copy you can make an exact copy of existing aggregate. It means that all volumes and qtrees that are on the source aggregate will be copied as well.
You can use aggr copy to copy the aggregate within the same filer or to another filer. If the destination is on another filer make sure that rsh authentication is enabled on the source and destination.
The basic example:

filerB> aggr restrict aggr_dest
filerB> aggr copy start filerA:aggr_source filerB:aggr_dest

snapshot copy

NetApp allows you to manually or automatically create and maintain many snapshot copies. Snapshot itself doesn’t copy the data when created, but copies the data that changes between the snapshot and the current state. It means that if you have a snapshot made yesterday at 12:00 you can at any time recover files or even the whole snapshot image to the point of yesterday 12:00.
The basic example:

filerA> snap create volume_01 snapshot_0001

With the snapshot ans SnapRestore (extra license is needed) you can easily recover single file or the whole volume from snapshot.

SnapMirror

With the snapmirror you can replicate the whole volume or the selected qtree to other location (extra license is needed) . You can set SnapMirror in three modes: sync, a-sync and semi-sync. More about SnapMirror you can find in this post.

SnapVault

SnapVault is the backup feature that requires and extra license.  Within the SnapVault you can back up the entire qtree, set up different snapshot schedule on the destination. More about SnapMirror vs SnapVault you can find in this post.

vol copy

With the vol copy you can copy all data from one volume to another, either on the same or different system. Similar to aggr copy, you can initiate a volume copy with the vol copy start command. Teh result is a restricted volume containing the same data as the source volume at the time you initiated the copy opreation.

filerA> vol create vol1 aggr1 50g
filerB> vol create vol1_copy aggr1 50g
filerB> vol restrict vol1_copy
filerB> vol copy start filerA:vol1 filerB:vol1_copy
 […]
filerA> vol status -b 
Volume     Block Size   Vol Size  FS Size 
 ——      ——        ——      ——
 vol1           4096             4346752            4346752
filerB> vol status -b
Volume     Block Size   Vol Size  FS Size 
——      ——        ——      ——
vol1_copy     4096             4346752            4346752 

filerB> vol online vol1_copy

Of course that’s just a simple example.

SyncMirror

Continous mirroring of data to two separate aggregates. This features allows for real-time mirroring of data to matching aggregates physically connected to the same storage system.