Thanks Charles.  Yes, these are issues to consider.  I was really just
looking to see what other people were getting.  HBA's are dedicated 4/
HBA on 8 Gbit cards.  I have a feeling it is a device driver issue, or
an issue with the IO cards in the Quantum.  Since they are HP drives,
I have to use the TSM device driver, and not Atape.  Just checking to
see if anyone else has experienced LTO5 not living up to published
speeds.

Also, I can read off the disk subsystem at 1000+ MB/s, so I'm
confident that the system is able to push data fast enough.  I am
getting proportional speed increases with number of drives.  IE 2
drives gives 100 MB/s and 8 gives 400 MB/s over 1-2 hours.

Thanks all.



On May 3, 2011, at 8:22 AM, Hart, Charles A wrote:

Few things to consider

1) Are the HBA's for the LTO5 Drives dedicated or do they have other
devices.

2) How many LTO drives per HBA?

3) Speed of Fibre 2/4/8Gb

....

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On
Behalf Of
Gary Bowers
Sent: Monday, May 02, 2011 9:39 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] LTO5 performance

Just a quick poll of what people are seeing for LTO-5 performance.  Is
it anywhere close to the rated 140 MB/s native, or much lower?  I ask,
because I have a customer that is only getting about 40-50 MB/s from
HP
LTO5 drives in a Quantum library.  This number seems really low to me,
but before I jump to making recommendations, I would like to have some
real world numbers to go off of.  You'd think Google would find some,
but my searches turned up nill.

As an aside, has anyone had performance problems with Quantum
libraries
and their built-in Fibre Switches?

OS is AIX 6, having the same performance from both TSM server, AIX and
Solaris 10 LanFree.

Thanks for sharing :)

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