topic Re: Disk performance for DB2 backups in HPE EVA Storage

Disk performance for DB2 backups

WCzar — Tue, 18 Aug 2009 17:50:52 GMT

We have a EVA3000 with three defined disk groups (146, 250 and 300 GB drives). The 146 and 300 drives are FC, the 250 drives are FATA. Need to connect a couple of W2K3 DB2 servers having only local disk. Backups are taken daily and are currently stored on local disk as well. Disk space is tight so we want to store the backups on the EVA. Restores are rare, but if necessary then recovery time would be a priority. Was initially leaning towards the FATA group. Can anyone make a recommendation as to which disk group would be best suited for use as a DB2 backup repository.

Re: Disk performance for DB2 backups

Sheldon Smith — Wed, 19 Aug 2009 21:12:24 GMT

The FATA drives are intended for light-duty work (say < 30%) as compared to your main FC drives. This means activities like holding archives and receiving backups of 'stuff'. If it were me, I'd be looking at adding HBAs to the W2K3 DB2 servers (if they don't already have them) and store the backups directly to the FATA group on the EVA.

Re: Disk performance for DB2 backups

WCzar — Thu, 20 Aug 2009 12:14:57 GMT

Then we will go with the FATA disk group. The HBAs will be 2 GB, so hopefully there won't be any backup or restore performance issues with the drives being near-online. We can create the vdisk as either raid0, 1 or 5. We would want to maximize the amount of disk space available. Raid 1 offers the least. Would you recommend Raid 0 or 5 considering the backup files on the EVA will be backed up to tape.

Re: Disk performance for DB2 backups

Sheldon Smith — Thu, 20 Aug 2009 13:43:31 GMT

I would recommend vRAID 5, and after rolling the backup to tape, keep it on the FATA disk group UNTIL you need to reuse that disk space to hold a subsequent backup. Restore time will be faster coming from the disk group rather than tape.
Depending on the size of the FATA disk group and the size of the DB2 backup, you may be able to perform multiple backups over the course of a day, with one (or more?) getting rolled off to tape.