2011-05-06 07:10 AM
We are planning data migration from 32bit aggregate to 64bit aggregate. We have many volumes with the snapshots.
Which all options are available to migrate data from 32bit aggregate to 64bit aggregate with snapshots and less downtime?
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2011-05-06 07:31 AM
If you can wait to migrate your data for a few more months, Data ONTAP 8.1 may have a 32 - 64-bit conversion feature that will save you from migrating data (It's on the roadmap, but like all things feature related - there are no guarantees when it will be released) If you need to move your data in the immediate future, the best option is Qtree SnapMirror (QSM). The process to migrate data and retain your snapshots is very similar to migrating from a Traditional Volume to a FlexVol. This KB article below has a lot of good detail on how to do that. The bad news is, be prepared to do a LOT of QSM migrations. Unless you need all of your hourly and daily snapshots, I would recommend only doing the last 24 hours of hourly, last 6 days of daily, and then the last 2 weekly snapshots. Over 90% of data restore requests are for the previous 2 weeks. Rely on tape or DR copies for requests beyond that.
If you can afford to take some downtime (and have a lot of disks), an alternative would be to disable all services, SnapMirror the active filesystems for each volume to your 64-bit aggregates, point all your CIFS shares/NFS exports to the new volumes, then renable all services. Hold onto the 32-bit aggregates until all the snapshots roll off (put the volumes in restricted mode to make sure no one can write to the volumes). It's essentially the same thing you do when transitioning to a new backup application - hold onto the old backup server and tapes to fulfill restore requests until the retention period is met.