ADSM-L

Re: 4.2.0 client backup performance

2001-10-30 16:36:55
Subject: Re: 4.2.0 client backup performance
From: Zlatko Krastev/ACIT <acit AT ATTGLOBAL DOT NET>
Date: Tue, 30 Oct 2001 23:34:20 +0200
3583 (and other LTO libs) is a "Speedy Gonsales" library in the Wintel
world. Only Magstar 3590-E1A drives are faster.
I would bet that your network is not so fast and direct-to-tape backup
writes in small portions with pauses in between. So start/stop of tape
consumes the main part of the time.
Do the math by yourself - 100Mb Fast Ethernet ~= 10-11 MB/s (! make the
difference between small "b" (bits) and capital "B" (bytes) !). Duplex does
not count because you are not doing simultaneous restores with backups,
aren't you. The LTO is capable of 15 MB native and 30 MB/s compressed. So
the drive is up to three times faster than the LAN and you cannot use
streaming mode features.
As you point also backup to disk takes 3-4 min which gives approx. 4 MB/s.
If this result is for many (i.e. small) files it is not so bad but for
larger files you can get more (7 MB/s is a good target). So you can have a
look at the network and client drives performance.
On the other side 800 MB for 45s gives approx. 17.78 MB/s which is good.
Use large enough disk pool for staging and everything should work fine.

Zlatko Krastev
IT Consultant





Gianni Garda <gianni.garda AT LABINF DOT IT> on 30.10.2001 12:19:27
Please respond to gianni.garda AT labinf DOT it
To:     ADSM-L AT VM.MARIST DOT EDU
cc:

Subject:        4.2.0 client backup performance

Hi all,


My scenario

Running a TSM Server 4.2.0 on Win2000 with 3583 Library

My problems is with performances backups of  Win2000 Client (4.2.0).
If the copy destination in backup copy groups is set to TAPEPOOL the
performance is very bad (18 Min. for 800Mb).
If the copy destination in backup copy groups is set to DISKPOOL the
performance is good (about 3-4 Min)
But the migration of 800Mb from TAPEPOOL to DISKPOOL is complete in about
45
seconds, so the write performance of the drive in library is good.

I don't know why this difference .
Any idea ?

P.S.
Sorry for my bad english.
===========================================
Gianni Garda
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