IO capacity on nPars and vPars

[Ian Dennison_1]

Have a number of large databases on an RP8420 which are struggling to push through backups to tape when running multiple drives.

The main culprit is a pair of vPars on the same nPar (made up of one cell only). We were looking at moving Databases from one vPar to another to spread the IO load.

Question: Does a bottleneck on one vpar on a cell affect the other vpars on the same cell?

Share and Enjoy! Ian

[Robin T. Slotten · Accepted solution]

Generally speaking, the 2 vPars should be isolated from each other as far as bottlenecks are concerned. No shared I/O devices. If you are using WLM and sharing processors, you could impact the other vPar, but you should be able to see that happening using WLM tools.

Possible issues could be both vPars accessing the same fiber switch and the switch causing a bottle neck, but in most cases the tape drive can't process data fast enough to overload the fiber network or the server for that matter.

If you are attempting to backup both servers across the LAN at the same time, you might be bottle necking in the LAN enviornment, but again, the tape drive is usually the limiting factor.

What tools have you used to determine a bottle neck?
Rob...