Allen,

My only thought - given that you are restoring lots of small files -
is that you may be thrashing the target disk. Have you looked at that ?

Ian Smith
Oxford
England


On Monday 03 Aug 2009 5:07 pm, Allen S. Rout wrote:
> Howdy, all.
>
> I've done a decent amount of small-scale online restores from my
> offsite virtual volumes, and never been particularly unhappy with the
> speed.  (though come to think of it I've never timed it either)
>
> But I'm restoring a pretty big volume now, and it's taking a L-O-N-G
> time.  I was hoping to elicit war stories from some of you, and see if
> my expectations are just out of whack.
>
>
> Environment: Everything is TSM 5.5.3 on AIX.  I've got about 350 miles
> between primary and secondary site.
>
>
> I regularly get 80 MB/s sustained running tape to tape from primary to
> offsite over this link.  I've got plenty of TCP buffer space, and I've
> set my TCP windows to be 2M on all the servers.
>
> When I use iperf to check just TCP/IP throughput, I get 800-900Mb
> avg. over 30 seconds, with sustained 1Gb plateaus.  So the network
> level seems reasonable.
>
> But the restore is rattling around in the vicinity of 2.5 MB/s; just
> incredibly slow.
>
> Now, these are small files; average is just 300K, and most of them are
> much smaller (email messages).  But the database on the restoring
> server isn't thrashing, I don't find any bottlenecks at first look.
>
>
> So.  What have you-all seen out of your restores?  I really need to
> characterise this; It would Not Be Good if this were the best I could
> do in a real emergency.
>
>
> - Allen S. Rout