NDMP Differential Backups

[ptate]

Hi Everyone,

I am familair with the TSM NDMP setup and have been taking full backups of NetApp devices successfully for some time.

However, we now have a need to perform nightly backups. In the course of the next 2 months we will create 18TB of new data on the NetApps - data is only added, never deleted or modified.

The largest volume we will have will be 6TB, which will take quite a while to backup even using NDMP. I believe that I have two options:

1. Use a combination of TSM Full and Differential backups
2. Using NetApp snapshots and then backing up those snapshots

Can anyone give me some advice on the pros and cons of each option (and whether I have any other options available to me)?

TSM 5.4.4
DataONTAP 7.3.1

Many thanks

Phill

[Eldoraan]

TSM can't backup a NetApp Snapshot, so that option is out. On a volume that size, even differentials will run for long time just pulling blocks together of changed files. I've got 2.5TB volumes that take a couple of days for full, and about a day by 3rd differential.

Depending on how the data is broken out, you may be able split it up using virtualfsmapping option. I've not used this myself, so not sure how much improvement you'll get. If you had volume /vol/data and then root level directories /homes, /shared, /admin then you could define virtualfsmaps for each and back them up concurrently if filer has bandwidth for amount of data. Read up on it and experiment. I wish I had more info, but I can't play much with my environment at moment.

[inestler]

we do daily differential and weekly full ndmp backups. our volume size is limited to 2TB.
you can also backup snapmirror (backup node xxx mode=full type=snapmir)

[Eldoraan]

SnapMirror backup is feature of TSM 6.1.... both ptate and my are running 5.4.4.x so not available to us.

[Canuck]

One of the options with the new TSM 6.1 client is the ability to backup the snapshot differences. This works on TSM 5.x servers.

I haven't tried it out yet but looks promising. IBM still recommends performing a full every once in a while since this is similar to performing an incremental by date but much faster. You would need to mount each volume as a CIFS share and back it up.

Also, you might end up having to use a combination of NDMP / Snapdiff for faster restores of entire volumes.

[copycat]

Hi,

we are using ndmp for our nSeries / netapp cifs backups directly to tape. this works fine. I tested to backup a specific snapshot. This worked for me. I used /vol/ourvolume/~snapshot/hourly.0 as a virtualfs. The next step is using snapmanager for VI to backup a nightly snapshot directly to tape. Is there anyone with experience? Will it give consistent restores? (isci lun)

Version 5, Release 5, Level 3.0
DataONTAP 7.3.4