Data ONTAP Discussions

SME6.0 Snapshot Retention Sizing

I am trying to size my LUN properly to hold my required number of snapshots for retention. I've looked around trying to determine if I need enough space for 8 days of rentention, since I don't know if SME will write the most recent file to disk first before deleteing the oldest snapshot or vice-versa. I have discovered that if I was creating snapshots from the System Manager, it would automatically delete enough old snapshots to free up 20% disk space for newer snapshots by default. But I haven't found anything documenting what SME would do. Where can I get this info?

For example, say I want to have 5 days of retention, and the daily snapshots are 20GB apiece. If I had a 110GB LUN, and a full five days of snaps, would SME delete the oldest snap, freeing up enough space for the newest snap? Or is there a setting that would check the disk size first, then delete up to a set amount to gain enough space before writing the new snap? Or would SME just error out and fail because there was not enough free space since it writes first, then deletes the oldest snap?


SME6.0 Snapshot Retention Sizing

Hi Mr. Braxlor,

Here the doc :

I hope it's help!



SME6.0 Snapshot Retention Sizing

SME sys-admin guide walks can answer you in step-by-step procedure, just look under retention.

Now, to point out coupld of things, like *must-know*:

- When you are backing up databases / applications, and if you use SME or for any case other backup products,like SnapManager products, then never configure System Manager OR ONTAP schduler to take/retain/delete backups or create/retain/delete manual backups. If you do, then, it will create holes in the backup products, like in this case is SME!

- If you want to configure "auto-deletion" based on a criteria like, storage capacity, retention based on number of days / quatiity based snapshots, then, you can schedule all this within SME

- In addition, you can setup thresholds for alarming, etc.. within the product as well!

Cheers, balbeer    

SME6.0 Snapshot Retention Sizing

Hains - Thanks for the document, I'll look through it.

Balbeer - I've looked through the Installation and Admin Guide and set up retention per the document, but it does not occur on my system. I can look through the logs and see where it states, 'Backups older than [5760] minutes ago will be deleted.' Yet, it also states 'No SnapInfo snapshots will be deleted.' However I have snaps 7 days old in both the SnapInfo location and ones being reproted in System Manger.

I have no other backups or snapshots being conducted on the data. So there is not a conflict here. In fact, no errors report at all. As far as SME thinks, everything is running the way it should be.