Re: [Bacula-users] Typical tape write performance

Paul Elliott wrote (2015/12/02): > I would be interested to hear what block sizes other LTO5/6 users are > using? LTO-5/SAS on FreeBSD: I still use Maximum Block Size = 65536, because 333 MB/s transfer rate is sufficient for me. I have tried this small script --- #!/bin/sh B=131072 C=32768

Re: [Bacula-users] Typical tape write performance

Dan Langille wrote (2015/12/02): > I had not considered that. In my case, I backup to local HDD (ZFS array) > for long term storage. Right after those jobs finish, I copy to tape. > Sounds like I need to implement spooling now. Fortunately, my full > backups are only about 400GB. I think I can

Re: [Bacula-users] Typical tape write performance

On 02/12/15 12:14, Paul Elliott wrote: >> Maximum block size = 2M > > Have you experienced any issues with that block size? Only when the drives/tapes are dirty and then you get excess errors on all block sizes anyway. Because entire blocks are rewritten if there is an error, "tape

Re: [Bacula-users] Typical tape write performance

On Wed, 02, Dec, 2015 at 03:04:07PM +, Alan Brown spoke thus.. > On 02/12/15 12:14, Paul Elliott wrote: > >> Maximum block size = 2M > >Have you experienced any issues with that block size? > Only when the drives/tapes are dirty and then you get excess errors on all > block sizes anyway.

Re: [Bacula-users] Typical tape write performance

> On Dec 2, 2015, at 10:04 AM, Alan Brown wrote: > > On 02/12/15 12:14, Paul Elliott wrote: > >>> Maximum block size = 2M >> >> Have you experienced any issues with that block size? > > Only when the drives/tapes are dirty and then you get excess errors on all >

Re: [Bacula-users] Typical tape write performance

On Nov 30, 2015, at 12:18 PM, Alan Brown wrote: > >> On 30/11/15 16:57, Christoph Litauer wrote: >> Hi Alan, >> >> maybe this is an important hint … >> I thought btape doesn't use a disk at all. Instead it uses on-the-fly >> generation of test data … does it? > > If it

Re: [Bacula-users] Typical tape write performance

>> For LTO, the Spool disk MUST be at least least one SSD, preferably a stripe of them on as fast a controller as you can afford. Standard disks simply can't keep up with tape drives. > I had not considered that. In my case, I backup to local HDD (ZFS array) for long term storage. Right after

Re: [Bacula-users] Typical tape write performance

Hi Alan, On Wed, 02, Dec, 2015 at 11:46:40AM +, Alan Brown spoke thus.. >You should also consider doing the following in bacula-sd tape drive >stanzas > Maximum File Size = 16G > Maximum Network Buffer Size = 262144 > Maximum block size = 2M Have you experienced any

Re: [Bacula-users] Typical tape write performance

Hi Christopher, It sounds like you have other bottleneck issues elsewhere either with your disks or tape drive/cabling which could be slowing things down. You might want to check for firmware updates for the tapes/disks/controllers. For LTO-4 your system needs to be able to sustain at least

Re: [Bacula-users] Typical tape write performance

On 30/11/15 15:32, Christoph Litauer wrote: > Andrew, > > many thanks for this hint. I installed the IBM driver and found the tape > drive testing tool itdt, too. > Now, using itdt and the new driver there is an improvement: > LTO6: 158 MB/s without compression, 177MB/s with compression > LTO4:

Re: [Bacula-users] Typical tape write performance

Hi Alan, maybe this is an important hint … I thought btape doesn't use a disk at all. Instead it uses on-the-fly generation of test data … does it? If btape uses the configured spool directory I have to take a look at that point. > Am 30.11.2015 um 17:00 schrieb Alan Brown

Re: [Bacula-users] Typical tape write performance

On 30/11/15 16:57, Christoph Litauer wrote: > Hi Alan, > > maybe this is an important hint … > I thought btape doesn't use a disk at all. Instead it uses on-the-fly > generation of test data … does it? If it does, that could easily be your bottleneck. /dev/random isn't normally very fast. > If

Re: [Bacula-users] Typical tape write performance

On 30/11/15 16:57, Christoph Litauer wrote: > Hi Alan, > > maybe this is an important hint … > I thought btape doesn't use a disk at all. Instead it uses on-the-fly > generation of test data … does it? If it does, that could easily be your bottleneck. /dev/random isn't normally very fast. > If

Re: [Bacula-users] Typical tape write performance

Andrew, many thanks for this hint. I installed the IBM driver and found the tape drive testing tool itdt, too. Now, using itdt and the new driver there is an improvement: LTO6: 158 MB/s without compression, 177MB/s with compression LTO4: 27 MB/s without compression, 128 MB/s with compression.

[Bacula-users] Typical tape write performance

Dear bacula users, I recently recognized that my tape drives do not perform as expected. Neither while used with bacula nor native with dd. I did many performance tests in the meantime but could not figure out the reason. So may I ask in this group what typical write speeds you have with your

Re: [Bacula-users] Typical tape write performance

Are you using the IBM Linux tape driver? If not, I'd suggest installing it vs the generic linux kernel's tape driver. http://www-933.ibm.com/support/fixcentral/swg/selectFixes?parent=Tape%2Bdrivers%2Band%2Bsoftware=ibm/Storage_Tape/Tape+device+drivers=1.0=Linux=all On 11/27/2015 08:43 AM,