ADSM-L

Re: Performance problems restoring to WindowsNT servers

2015-10-04 17:51:03
Subject: Re: Performance problems restoring to WindowsNT servers
From: Toora, Kuli [mailto:kulbinder.toora AT EXCHANGE.MEB.CO DOT UK]
To: ADSM-L AT VM.MARIST DOT EDU
Hello folks,

I have read on a couple of recent e-mails that some users in the real world
are managing to get around thoughput problems by 'multistreaming'.
This is something that i and my installation would be very interested in.
Can any one give me any information on how to implement this on UNIX clients
and NT clients?.

We have am MVS server running 3.1.1.2 (soon to be 3.1.1.3 and then 3.1.2.0)
running through an ATM backbone.

Many Thanks,

Kuli.

Kulbinder Toora
Midlands Electricity
Kulbinder.Toora AT MEB.CO DOT UK


> -----Original Message-----
> From: Kelly J. Lipp [SMTP:lipp AT STORSOL DOT COM]
> Sent: Tuesday, November 03, 1998 3:47 PM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Re: Performance problems restoring to WindowsNT servers
>
> Trevor,
>
> We performed some limited restore performance testing at a site very
> similar to yours: H50 w/ 3575 robot.  Relatively small numbers of large
> files, >5 MB with the average somewhere around 6 or 7.  I don't know what
> the file restore rate was, but we were able to see 6 GB/hour with a single
> stream and it scaled linearly up to 18 GB/hour with three streams running.
>  The client was a rather small NT system: 128 MB, 300 MHz processor and
> three SCSI disks.  We restored one stream per disk.  The data was coming
> from both disk and tape on the server.  The performance was actually
> better
> coming off the tape than the disk.  Could be the reduced RAID set causing
> this though.
>
> I was pleased.  I saw no visible delay from the time I hit the carriage
> return and data started flowing.
>
> This was a new installation.  Smallish DB with smallish numbers of files
> overall in the entire system.  So perhaps my test was not valid compared
> to
> your situation.  But you are right, something seems amiss.
>
> Kelly Lipp
> Storage Solutions Specialists, Inc.
> lipp AT storsol DOT com
> www.storsol.com
> (719) 531-5926
>
> -----Original Message-----
> From:   Trevor Foley [SMTP:Trevor.Foley AT BANKERSTRUST.COM DOT AU]
> Sent:   Tuesday, November 03, 1998 12:39 AM
> To:     ADSM-L AT VM.MARIST DOT EDU
> Subject:        Performance problems restoring to WindowsNT servers
>
> Hi,
>
> We are getting ready for our first disaster recovery test this weekend
> using
> ADSM as our exclusive backup utility. We have been doing some test
> restores,
> and things are looking pretty gloomy. Our major focus is WindowsNT, but
> other platforms seem to be having problems also.
>
> The systems that we are testing have very large numbers (some in excess of
> 1
> million) of active backup files on a single filespace, most of which are
> very small. So we expect some amount of delay before data starts moving on
> a
> restore. But we are seeing extremely poor performance. One of the test
> restores, for an entire volume, resulted in 1.3 files per second being
> restore. When you talk about 1 million files, that is a long time. Another
> test, this time for only one directory tree, restored 143 files in 38
> minutes; much worse. This second restore we see very long pause times with
> no noticable activity; no volume mounts, the session in 'Run' state, and
> the
> GUI (yes, I know that the the command line may give better performance but
> I
> tried the command line and saw no noticable difference) showing the same
> filename being processed and the status bar showing no data transferred
> for
> that file. I then did a contrived test by backing up a set of files to a
> disk pool, and then restoring them. This resulted in 11 files per second
> being restored, which is getting close to acceptable.
>
> So, I guess what I am after are some suggestions as to what I could try to
> improve things, and some idea of what sort of performance others are
> experiencing. Note that the restores are coming from systems that have
> been
> ADSM clients for many months and therefore have data spread across
> multiple
> (the worst that I have seen is 9) collacted volumes.
>
> Our environment is:
>
> *       ADSM Server 3.1.2.0 on AIX using an R50 server and 3590 drives in
> a
> 3494 library
> *       WindowsNT 4.0 SP3 clients using 3.1.0.3
>
>
> regards,
>
> Trevor
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