Asking here because we don't have current Overland support for the fibre channel card and I would guess it is more of a problem with the card rather than netapp (we only used the FCO with a netapp), but maybe someone has encountered this...
Around 2004 we bought a Overland Neo 2000 tape library with the FCO VIA scsi to FC converter board, and we got at most 20 or 25MB/sec through it (per tape drive) depending if we were writing or reading. This is both with NDMP dumps from the filer disks to tape, and also across the network into the filer to tape with NDMP. The backup software is Bakbone Netvault. Last year we tried attaching this library to a Unix host directly with SCSI and our speed almost doubled. I was floored, and shocked that we spent so many years missing out on performance, although 20-25 was the best I've seen anyone report for LTO2 so I never expected more.
Recently we bought another Neo 2000 with LTO4 drives, and I decided to move the FCO card over to it and try again, hoping maybe there was a misconfiguration, but I could not find any and it still acts as if there is a mystery cap on the speed of 20MB/sec (it averages 18-19 after it gets going). I've been all through the configuration of the FCO card and it is set to 160M/sec per scsi bus, tried with and without domain validation, and I even got the FC channel to operate at 2Gbit but no improvement. If I cannot figure this out then I will just attach it to the Unix host with the other neo 2000, but its always nice to have more options. I would not bother operating a LTO4 drive at such a slow speed in production because shoe-shining would probably wear it out and the compression would be sub optimal or non-existent.
Couple of thoughts, increasing the number of buffers, within the performance tab of configure for the tape drive and changing the block size.
Cheers
Matt
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Adam McDougall Sent: 09 May 2008 16:02 To: Toasters Subject: Max of 20MB/sec through FC attached LTO tape drive? Overland neo 2000
Asking here because we don't have current Overland support for the fibre
channel card and I would guess it is more of a problem with the card rather than netapp (we only used the FCO with a netapp), but maybe someone has encountered this...
Around 2004 we bought a Overland Neo 2000 tape library with the FCO VIA scsi to FC converter board, and we got at most 20 or 25MB/sec through it
(per tape drive) depending if we were writing or reading. This is both with NDMP dumps from the filer disks to tape, and also across the network into the filer to tape with NDMP. The backup software is Bakbone Netvault. Last year we tried attaching this library to a Unix host directly with SCSI and our speed almost doubled. I was floored, and shocked that we spent so many years missing out on performance, although 20-25 was the best I've seen anyone report for LTO2 so I never expected more.
Recently we bought another Neo 2000 with LTO4 drives, and I decided to move the FCO card over to it and try again, hoping maybe there was a misconfiguration, but I could not find any and it still acts as if there
is a mystery cap on the speed of 20MB/sec (it averages 18-19 after it gets going). I've been all through the configuration of the FCO card and it is set to 160M/sec per scsi bus, tried with and without domain validation, and I even got the FC channel to operate at 2Gbit but no improvement. If I cannot figure this out then I will just attach it to the Unix host with the other neo 2000, but its always nice to have more options. I would not bother operating a LTO4 drive at such a slow speed
in production because shoe-shining would probably wear it out and the compression would be sub optimal or non-existent.
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We've been using 65537k for transfer buffers for at least half a year at the recommendation of some docs, and 16384k before that. We also used 64k block size on the LTO2 tapes because it gained us a few megabytes per second (128k did not work), but I hope to avoid going over approx 63k because some operating systems need tuning or kernel hacking to do larger transfers than 64k. We have not attempted a direct SCSI connection with LTO4 yet (maybe next week, not on a Friday afternoon before the weekend backups start).
Davies,Matt wrote:
Couple of thoughts, increasing the number of buffers, within the performance tab of configure for the tape drive and changing the block size.
Cheers
Matt
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Adam McDougall Sent: 09 May 2008 16:02 To: Toasters Subject: Max of 20MB/sec through FC attached LTO tape drive? Overland neo 2000
Asking here because we don't have current Overland support for the fibre
channel card and I would guess it is more of a problem with the card rather than netapp (we only used the FCO with a netapp), but maybe someone has encountered this...
Around 2004 we bought a Overland Neo 2000 tape library with the FCO VIA scsi to FC converter board, and we got at most 20 or 25MB/sec through it
(per tape drive) depending if we were writing or reading. This is both with NDMP dumps from the filer disks to tape, and also across the network into the filer to tape with NDMP. The backup software is Bakbone Netvault. Last year we tried attaching this library to a Unix host directly with SCSI and our speed almost doubled. I was floored, and shocked that we spent so many years missing out on performance, although 20-25 was the best I've seen anyone report for LTO2 so I never expected more.
Recently we bought another Neo 2000 with LTO4 drives, and I decided to move the FCO card over to it and try again, hoping maybe there was a misconfiguration, but I could not find any and it still acts as if there
is a mystery cap on the speed of 20MB/sec (it averages 18-19 after it gets going). I've been all through the configuration of the FCO card and it is set to 160M/sec per scsi bus, tried with and without domain validation, and I even got the FC channel to operate at 2Gbit but no improvement. If I cannot figure this out then I will just attach it to the Unix host with the other neo 2000, but its always nice to have more options. I would not bother operating a LTO4 drive at such a slow speed
in production because shoe-shining would probably wear it out and the compression would be sub optimal or non-existent.
This e-mail (including all attachments) is confidential and may be privileged. It is for the exclusive use of the addressee only. If you are not the addressee, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please erase all copies of the message and its attachments and notify us immediately at help@generalatlantic.com mailto:help@generalatlantic.com. Thank You.
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Adam McDougall -
Davies,Matt