Hiya,
I think I can see what you are trying to get at, but what I am curious about
is whether the 20MB/s from your disks is due to a physical SCSI bus
restriction, eg your disks are all attached on one 20MB/s SCSI bus, or
whether your 20MB/s is a speed you've seen through some monitoring tool, as
you're disks could peak at higher rates depending on the type of I/O
activity.
Either way it is hard say put an estimate as to whether running two
migrations will cause be "bottlenecked" by the disks. You need to take into
consideration many things such as whether the data on disks is compressed
from the client or not. We can access our TSM disks at around 100MB/s and
can run 10 concurrent migrates to LTO1 drives, but when we have the 10
migrates running I always seem to see the disk throughput to be between
40-60MB/s, and never hitting the available throughput of the disks.
Sorry that I cannot offer any specific advice, but I hope that this gives
you some thoughts on the problem.
Many thanks
Andy Wilcox
UNIX Systems Administrator
Aquila Networks
-----Original Message-----
From: Patrick Rainer [mailto:Patrick.Rainer AT ARZ.CO DOT AT]
Sent: 03 March 2004 14:36
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Antwort: Re: 2 LTO-Drives Load-Balancing
Hello again
Sorry. Maybe my question can be wrong interpreted.
For example:
I have two migration processes from disk stgpool to tape drive.
My diskdrives offer about 20MB/s.
The question:
Is the transferrate of the diskdrives split up for the tape drives to 50%
for each drive? (10MB/s per drive) (Also means 50% per process)
Or uses one drive the full transferrate which is possible for one drive
(15MB/s) and the other drive only gets the rest (5MB/s)?
My problem -> 5MB/s means permanent Stop-and-Go-mode for one drive.
I would like to hear, that the TSM-server splits up the transferrate. This
means each migration process/job uses 10MB/s.
Thank you.
Best regards
Patrick
Karel Bos <Karel.Bos AT NUON DOT COM>
Gesendet von: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
03.03.2004 15:04
Bitte antworten zu
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
An
ADSM-L AT VM.MARIST DOT EDU
Kopie
Thema
Re: 2 LTO-Drives Load-Balancing
TSM is not load-balancing on a drive level. TSM will use multiple drives
on
a job level.
Regards,
Karel
-----Oorspronkelijk bericht-----
Van: Patrick Rainer [mailto:Patrick.Rainer AT ARZ.CO DOT AT]
Verzonden: woensdag 3 maart 2004 14:41
Aan: ADSM-L AT VM.MARIST DOT EDU
Onderwerp: 2 LTO-Drives Load-Balancing
Hello TSM users, a.a.o.o
I searched the mailinglist archive and the discussion forum, but did not
found a solution for my problem.
We are using TSM 5.2.2.1 for library evaluation. We are testing a HP
MSL5030 with two LTO1 drives.
Our disks provide a datarate of about 20MB/s.
LTO1 supports a datarate of maximum 15MB/s and starts STOP-and-GO-Mode at
about 7MB/s.
My question:
Is the TSM-Server balancing the load of the two drives?
That means: Every drive gets about 10MB/s
Or gets one drive 15 MB/s and the other only 5 MB/s?
We tried to analyze this load, but it isn't that simple. The only way is
to calculate the load out of the transfered bytes and the needed time.
How is it possible to monitor the load of one drive?
(HP told us, we shoud check if the LED's are blinking slow or fast ?!?)
Any ideas??
Best regards
Patrick
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Security: Internet e-mail is not a 100% secure communications medium.
Viruses: This e-mail (and any attachments) has been checked (using Sophos Sweep
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Therefore neither Aquila Networks Services Ltd nor Midlands Electricity plc or
any of their group undertakings (as defined by the Companies Act 1989)
(together referred to as the "Companies") accept legal responsibility for this
message or liability for the consequences of any computer viruses which may
have been transmitted by this e-mail.
Monitoring: All electronic communications with the Companies may be monitored
in accordance with the UK Regulation of Investigatory Powers Act, Lawful
Business Practice Regulations, 2000. If you do not consent to such monitoring,
you should contact the sender of this e-mail.
Aquila Networks Services Limited,
Registered office: Whittington Hall, Whittington, Worcester, WR5 2RB
Registered in England and Wales number 3600545
This e-mail may be sent on behalf of any of the Companies.
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