It looks to me like hdisk4 is saturated with IO. What's on it? DB? Logs? Disk storage
pool? Sequential storage? One big conglomeration of everything?
You don't say what the storage server is. Maybe it could use more cache.
One of the problems with SANs is that AIX still sees them as simple disk devices, and
therefore the serializations that apply to real disks are still used.
If hdisk4 is really big, it may be useful to redefine it as several smaller disks and
use standard AIX facilities like striping to increase the number of concurrent IOs.
You could also separate your database/log/disk storagepools into several TSM volumes
on different disks.
These days, a lot of shops make everything RAID5 without thinking about it. I'd
debate whether RAID5 is useful for TSM diskpools. I'm an old mainframer with DB2
experience, and there the trick was always to access your disks sequentially where
possible. The physics hasn't changed and RAID5 scatters your stuff all over the disks
turning sequential access into random access. AIX will do smart read aheads were it
detects sequential access and surely a migration is sequential in nature. Can anyone
with knowledge comment on TSM database access patterns? If these are often sequential
event the DB might be better off on JBOD disk.
OK. so once you've got your data placement organized, run your test again.
If its still unacceptable, check the archives for tips about database buffering.
Regards
Steve Harris
AIX and ADSM (TSM on Thursday!) Admin
Queensland Health, Brisbane Australia
>>> Chuck Lam <[EMAIL PROTECTED]> 11/07/2001 9:46:30 >>>
Server: M80 running AIX 4.3.3, 4GB RAM, 768MB ps
DiskStoragePool, Rlog, & Database on all on a
SAN via fibre channel connection.
TSM version: 4.1
This is a newly configured system. We are conducting
tests on it. When we tried to do a few backups by
themselves, they seemed to get done pretty fast.
However, when we had 4 migration processes and a
couple of backups going at the same time, everything
slowed down to a halt. According to my client, his
backup transfer speed was about 100MB per minute. Can
anyone give me some suggestions to improve the
performance? I have attached the 'topas' reading of
this server.
TIA
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