Hello,
I just want to mention that IBM LTO
tape drives spin down the speed. IBM LTO3 and IBM LTO4 has the same lowest
speed of 30 MB/sec. And in addition IBM LTO4 has an internal buffer of
512 MB. The mention shoe shine or start/stop effect will (normally) not
influence your backup / restore speed.
Have you the same tuning parameters
for LTO3 and LTO4, like buffer size and numbers of buffers?
Mit freundlichen Grüßen / Kind regards
Josef Weingand
IT Specialist
STG Technical Sales Systems Storage
-------------------------------------------------------------------------------------------------------------------------------------------
IBM Deutschland
Hollerithstr. 1
81829 München
Phone: +49-171 5526783
E-Mail: weingand AT de.ibm DOT com
-------------------------------------------------------------------------------------------------------------------------------------------
IBM Deutschland GmbH / Vorsitzender des Aufsichtsrats: Erich Clementi
Geschäftsführung: Martin Jetter (Vorsitzender), Reinhard Reschke, Christoph
Grandpierre,
Matthias Hartmann, Thomas Fell, Michael Diemer
Sitz der Gesellschaft: Stuttgart / Registergericht: Amtsgericht Stuttgart,
HRB 14562 WEEE-Reg.-Nr. DE 99369940
From:
| Rusty.Major AT sungard DOT com
|
To:
| Ed Wilts <ewilts AT ewilts DOT org>
|
Cc:
| "WEAVER, Simon \(external\)"
<simon.weaver AT astrium.eads DOT net>, veritas-bu AT mailman.eng.auburn DOT edu,
veritas-bu-bounces AT mailman.eng.auburn DOT edu
|
Date:
| 07.04.2009 22:10
|
Subject:
| Re: [Veritas-bu] LTO4 Performance With
Exchange 2003 IS Poor |
Very nice break down, Ed. This type of situation is where the need for
disk storage units becomes more and more apparent. It's getting harder
and harder to stream at the speeds faster tape drives need to stay running
at an acceptable level.
Just because the drive CAN go faster doesn't mean it WILL, all other things
remaining the same.
Not a knock on you, Simon.
Rusty Major, MCSE, BCFP, VCS ▪ Sr. Storage Engineer ▪ SunGard Availability
Services ▪ 757 N. Eldridge Suite 200, Houston TX 77079 ▪ 281-584-4693
Keeping People and Information Connected® ▪ http://availability.sungard.com/
P Think
before you print
CONFIDENTIALITY: This e-mail (including any attachments) may contain
confidential, proprietary and privileged information, and unauthorized
disclosure or use is prohibited. If you received this e-mail in error,
please notify the sender and delete this e-mail from your system.
Ed Wilts <ewilts AT ewilts DOT org>
Sent by: veritas-bu-bounces AT mailman.eng.auburn DOT edu
04/07/2009 10:19 AM
|
To
| "WEAVER, Simon (external)"
<simon.weaver AT astrium.eads DOT net>
|
cc
| veritas-bu AT mailman.eng.auburn DOT edu
|
Subject
| Re: [Veritas-bu] LTO4 Performance With
Exchange 2003 IS Poor |
|
On Tue, Apr 7, 2009 at 8:12 AM, WEAVER, Simon (external) <simon.weaver AT astrium.eads DOT net>
wrote:
Environment:
NBU 5.1 MP5 Master Plus many SAN SSO Media Servers Win2k3 SP2
Problem: Mail Backups of Information Store using LTO4 SL500 are taking
4 1/2 hours extra to backup compared to LTO3.
If the tape drives were not your bottleneck before - i.e.
you were continually driving them at least 80MB/sec, then upgrading
to LTO-4 will likely slow your backups down. By my calculations,
you weren't bottlenecked at the tape drives. You were taking 4 hours for
1TB of data. That's a total of 69MB/sec. If you were doing
that to 3 drives, you were only averaging 23MB/sec per drive.
LTO drives must stream. If you can't feed them data fast enough,
you'll shoe-shine the drives with continuous start/stop fashion and performance
will suck.
Same configuration is in place (ie: 3 streams to 3 different drives) and
all part of the same fabric, apart from being in a different building.
An IBM LTO4 drive requires a MINIMUM of 30MB/sec. An HP LTO4 requires
a MINIMUM of 40MB/sec. That's assuming no compression. If you're
compressing with a 2:1 ratio, you'll need double that. They top out
at 120MB/sec native and 240MB/sec with (2:1) compressed data.
So let's assume 2:1 compression on 3 streams going to an HP drive. You'll
need to deliver 2*3*40MB/sec, or 240MB/sec at an absolute minimum. You
can deliver up to 2*3*120 or 720MB/sec.
Since you were only averaging 23MB/sec per drive before,
you've got a LONG way to go.
.../Ed
Ed Wilts, RHCE, BCFP, BCSD, SCSP, SCSE
ewilts AT ewilts DOT org_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
_______________________________________________
Veritas-bu maillist - Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
|