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Some Q&A from a corporate client regarding dedupe

IHAC (enterprise level) who has the following conerns regarding Dedupe. I have answered them but am posting them for verification purposes. Any help would be highly appreciated. My answers are in italic.

  • Are NetApp de-duplication licenses free?

     Yes for lifetime

  • Known install base of NetApp de-duplication (how many firms are currently using NetApp de-duplication feature and for how long)

     Can some one help me with this?

  • Any known issues (performance, data corruption etc) related to deploying de-duplication in large enterprise

     No

  • Any relation between NetApp de-duplication and disk scrubbing.

     No.

  • Since snapmirror in synchronous mode is not supported by NetApp de-duplication; only snapmirror  in async mode can be used during user data migration from one system to another. Is there a better solution/recommendation from NetApp?

     No.

  • If for some reason there is not enough space to undeduplicate a volume, the undeduplicate process stops, sends a message about insufficient space, and leaves the volume de-duplicated; data or snapshot copies need to be deleted to provide the required free space; any better solutions/recommendations from NetApp?

     No.

  • Backups to a tape, either through NDMP or native dump command, does not preserve deduplication.  A full volume restore from tape backup can only be performed in stages, therefore, it would seem that anyone with aggressive SLAs and a full deduped volume would be well advised to have a snapmirror copy of it standing by, as you won't be able to restore it as fast as a regular volume. Any better solutions/recommendations from NetApp?

     To preserve deduped space snapmanager to tape (sm2t) must be used.

Re: Some Q&A from a corporate client regarding dedupe

Can some one help me with this?

http://www.netapp.com/us/company/news/news-rel-20100511.html

Any relation between NetApp de-duplication and disk scrubbing.

Any known issues (performance, data corruption etc) related to deploying  de-duplication in large enterprise

You can find some performance-related and application compatibility-related thoughts in extremely useful TR-3505 Deduplication Best Practices

Since snapmirror in synchronous mode is not supported by NetApp  de-duplication; only snapmirror  in async mode can be used

It's possible to use (sync), but it can bring you many unpredictable performance issues at source and destination side, so officially it's not supported together.

To preserve deduped space snapmanager to tape (sm2t) must be used.

Be careful with deduplicated data moved outside extremely reliable  RAID-DP data storage. It can be unsafe, if you will got a some "bad  block" onto deduplicated (i.e. not redundant) dataset.