Joshua Baker-LePain wrote:
On Tue, 7 Nov 2006 at 12:39pm, Plant, Dean wrote
I am currently testing an Overland Tape storage unit with a LTO-3 drive on CentOS 4.4. After a random amount of time but usually when we have backed up about 0.5-1TB we get scsi errors which cause the backup to fail. I have rebuilt the box with Solaris 10 x86 and Windoze to prove the hardware and have successfully backed up over 3TB on each OS without error.
Can anyone offer advice on how to find out what is causing the error in CentOS.
Your best bet to track down exactly what those errors mean would be to head over to the linux-scsi list. But I can tell you that I've been using an Overland LTO3 library on centos-4 for over a year now with very good results. The 2 main differences are that I'm using an x86_64 server (I doubt that makes much difference) and an LSI 21320 HBA. I have had nothing but good luck with LSI adapters, and I think it'd be worth it for you to give one a shot.
I will say this, though. If you plan on ever using 2 drives in the library, get the 22320, which has 2 external channels. I've been tearing my hair out trying to get both drives in my library to write at full speed at the same time, and no matter what driver tweaks I make, I just can't get it to go. My 22320 arrives today, and I'm rather hoping that'll fix the problem.
Thanks for your reply,
I think ill try the LSI adapter, as your setup seems very similar. Just out of curiosity what sort of backup speeds do you get to a single LTO3 drive?. I seem to struggle to get anything above 60-70MB/s.
Dean.
On Tue, 7 Nov 2006 at 3:19pm, Plant, Dean wrote
I think ill try the LSI adapter, as your setup seems very similar. Just out of curiosity what sort of backup speeds do you get to a single LTO3 drive?. I seem to struggle to get anything above 60-70MB/s.
Yeah, 70MB/s is about my top speed as well (both via 'tar -b 4096' and amanda with a 2MB blocksize). Given that the drives are rated at 80MB/s, I'm not too unhappy with that.
On Tue, 07 Nov 2006, Joshua Baker-LePain wrote:
On Tue, 7 Nov 2006 at 3:19pm, Plant, Dean wrote
I think ill try the LSI adapter, as your setup seems very similar. Just out of curiosity what sort of backup speeds do you get to a single LTO3 drive?. I seem to struggle to get anything above 60-70MB/s.
Yeah, 70MB/s is about my top speed as well (both via 'tar -b 4096' and amanda with a 2MB blocksize). Given that the drives are rated at 80MB/s, I'm not too unhappy with that.
Apologies for hijacking the thread, but I'm seeing speeds of only around 30MB/s with an LTO3 library connected via 2Gb fibre channel, both with tar and with Bacula.
Would you know how to go about investigating this?
Adam
On Wed, 8 Nov 2006 at 12:21pm, Adam Huffman wrote
Apologies for hijacking the thread, but I'm seeing speeds of only around 30MB/s with an LTO3 library connected via 2Gb fibre channel, both with tar and with Bacula.
Would you know how to go about investigating this?
What blocksize are you using? That has the biggest impact on tape performance of any of the factors I've looked at.
On Wed, 8 Nov 2006, Joshua Baker-LePain wrote:
Date: Wed, 8 Nov 2006 07:43:23 -0500 (EST) From: Joshua Baker-LePain jlb17@duke.edu Reply-To: CentOS mailing list centos@centos.org To: CentOS mailing list centos@centos.org Subject: Re: [CentOS] Problems with LTO-3 and U320 on Centos 4.4
On Wed, 8 Nov 2006 at 12:21pm, Adam Huffman wrote
Apologies for hijacking the thread, but I'm seeing speeds of only around 30MB/s with an LTO3 library connected via 2Gb fibre channel, both with tar and with Bacula.
Would you know how to go about investigating this?
What blocksize are you using? That has the biggest impact on tape performance of any of the factors I've looked at.
I had some experiences with much slower systems (both tapes, connections and CPU/memory) when to get any performance close to rated tape speed, I had to use buffering (there was buffer utility); I guess -fifo feature of star should be looked at.
Wojtek
On Wed, 8 Nov 2006, Wojtek.Pilorz wrote:
On Wed, 8 Nov 2006, Joshua Baker-LePain wrote:
Date: Wed, 8 Nov 2006 07:43:23 -0500 (EST) From: Joshua Baker-LePain jlb17@duke.edu Reply-To: CentOS mailing list centos@centos.org To: CentOS mailing list centos@centos.org Subject: Re: [CentOS] Problems with LTO-3 and U320 on Centos 4.4
On Wed, 8 Nov 2006 at 12:21pm, Adam Huffman wrote
Apologies for hijacking the thread, but I'm seeing speeds of only around 30MB/s with an LTO3 library connected via 2Gb fibre channel, both with tar and with Bacula.
Would you know how to go about investigating this?
What blocksize are you using? That has the biggest impact on tape performance of any of the factors I've looked at.
I had some experiences with much slower systems (both tapes, connections and CPU/memory) when to get any performance close to rated tape speed, I had to use buffering (there was buffer utility); I guess -fifo feature of star should be looked at.
Wojtek
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
I've been able to push a single LTO2 tape to 93-96MB/s and single LTO3 tape to 137-139MB/s. Note, the drive is an HP-Ultrium2-SCSI and HP-Ultrium3-SCSI and nothing else was connected to the SCSI bus. I used NetBackup to perform the tests with various levels of multiplexing.
Justin.
On Wed, 8 Nov 2006 at 9:55am, Justin Piszcz wrote
I've been able to push a single LTO2 tape to 93-96MB/s and single LTO3 tape to 137-139MB/s. Note, the drive is an HP-Ultrium2-SCSI and HP-Ultrium3-SCSI and nothing else was connected to the SCSI bus. I used NetBackup to perform the tests with various levels of multiplexing.
*And* your data was obviously fairly compressible. Native rated speed for LTO3 is 80MB/s.
On Wed, 8 Nov 2006, Joshua Baker-LePain wrote:
On Wed, 8 Nov 2006 at 9:55am, Justin Piszcz wrote
I've been able to push a single LTO2 tape to 93-96MB/s and single LTO3 tape to 137-139MB/s. Note, the drive is an HP-Ultrium2-SCSI and HP-Ultrium3-SCSI and nothing else was connected to the SCSI bus. I used NetBackup to perform the tests with various levels of multiplexing.
*And* your data was obviously fairly compressible. Native rated speed for LTO3 is 80MB/s.
-- Joshua Baker-LePain Department of Biomedical Engineering Duke University
Correct, I optimized all settings I could find. I used a file that was all A's, i.e.: AAAAAAAAA and placed it on a ram disk. I wanted to see how far I could push the drive/tape.
With regular filesystem data, I hit 90-127MB/s depending on the level of multiplexing.
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Adam Huffman -
Joshua Baker-LePain -
Justin Piszcz -
Plant, Dean -
Wojtek.Pilorz