ADSM-L

Re: DISK Storage Pool Performance

1999-07-29 06:02:34
Subject: Re: DISK Storage Pool Performance
From: Steve Diver <SDiver AT TANDB.CO DOT UK>
Date: Thu, 29 Jul 1999 11:02:34 +0100
Grant.

We use disk storage pools on SSA disks and have no performance problems. 
However we use raw LV's for the volumes rather than files in a filesystem.

Just create the LV's to the required size and then define them to the ADSM 
storage pool -
        DEF VOL <STGPOOLNAME>  /dev/r<LVNAME>
don't forget to put the 'r' before the LVNAME. (No need for dsmfmt in this 
case).

Steve!

>>> "Cohn, Grant" <Grant.Cohn AT SAPREF DOT COM> 07/29/99 10:27am >>>
Greetings all

I have just tried to use SSA disks as a primary storage pool for one of our
NT clients (running ADSM 3.1.0.7)

1. I created a storage pool with a device class of DISK (Using RS6000 AIX
4.1.5 & ADSM server 3.1.2.20)
2. Formatted 10 1.5 Gb files on the SSA disks using dsmfmt -m -data
xxxxxxxxxxxx 1500
3. Defined these disk storage pools to my storage pool created in 1. above
4. Created a Mgmnt class to use this new storage pool
5. Changed my dsm.opt file on the NT server to use this mgmnt class
6. Ran a first-time incremental backup on one of the drives.

While the backup was executing I noticed that all 10 of my disk storage
volumes were being used at the same time, i.e. they were all filling at the
same time.

Worst of all - this backup took 1h45 mins to backup 2.8 Gb.
To compare, I am backing up 20Gb to tape in 2h10mins on another NT server
connected on the same network.

Anybody with ideas, firstly why it used all 10 volume (disk files) at the
same time, and secondly why the performance is so slow. I would expect disk
storage to be faster.


Many thanks

Grant Cohn
Shell & BP Petroleum Refineries
Prospecton
DURBAN
South Africa.

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