>> On Wed, 23 May 2007 06:17:30 -0600, James Choate <jchoate AT CHOOSES1 DOT 
>> COM> said:


> Does anyone have any general information that they have collected on
> restore time?

General timing information is nearly useless; not really.  Some of the
questions I'll ask below will amplify that. :)


> Were trying to do a restore, and but we're not sure what to expect,
> and we don't have anything to compare it to.


> We are currently restoring 8.17GB to a Windows 2003 server.
> The client is running on IBM x345 hardware.

> The TSM server is a p660 with 2GB memory and 4-HBAs (2 for disk and
> 2 for tape) AIX 5305.  I have 14 LTO2 tape drives.

Well, this part is clearly Really Darn Fast. ;)

> The TSM server is TSM 5.4.
> When I backup an 8GB Windows client to the TSM server, it takes 18 minutes.
> When I restore from the disk storage pool, it takes 43 minutes.
> When I restore from the tape storage pool it takes 60 minutes.


What's the disk tech of the client?  It seems to be writing 3MB/s: is
that what you get there normally?  Is anything else happening on the
accepting client?

Is the restore a few big files, or many little files?  Often, for the
small-file case, file system overhead can swamp any throughput
desires.

The tape being substantially slower than the disk is reasonable: not
so many disk techs can stream writes as fast as a tape can stream
reads. :) That's actually pretty good backhitch impact, I hadn't
thought LTO so deft.

When you back up it's to a disk-based landing pad, right? (be it DISK
or FILE devclass) What's the disk underneath that?  You're only
backing up at ~8M/s: That feels like 100Mb to me, not Gb.  Are you
sure you're getting good throughput at the network level?



So, examples that won't help:

I have a p630, with a bunch of SSA disk underneath it, and I usually
get 30MB/s backup for a single stream, and can usually restore it from
disk at the recieving boxes' disk-write bottleneck speed.


- Allen S. Rout