I have not set the Maximum File Size for my tape devices as I assumed this was only for file based backups. I now see https://docs.bareos.org/bareos-19.2/TasksAndConcepts/AutochangerSupport.html#tapespeed-and-blocksizes points to changing this value. Is there a recommendation for LTO-8 and LTO-9 devices?
It looks like changing the Maximum Block Size can be a challenge to keep compatibility with older backups. Does changing this make a large difference in performance and make it worth the risks? On Monday, April 14, 2025 at 11:49:13 AM UTC-5 Andreas Rogge wrote: > Hi Jon, > > what's your Maximum File Size setting on the tape device? > The default of 1 GB will not perform very well with recent tape drives, > as it is way too low and flushes the drive buffer far too often. > > For encryption/decryption the drives can definitely do this at > line-speed. I haven't seen any performance impact with LTO encryption yet. > > Best Regards, > Andreas > > Am 10.04.25 um 18:07 schrieb Jon Schewe: > > Bruno, > > > > I understand it's a decrypt and decompress, transfer data and then do it > > over again. I would hope that the hardware could do encryption and > > compression at line rate. > > So you're thinking it's hardware and there aren't things I should change > > in bareos? I'm assuming that tape to tape copies should not spool, is > > that a reasonable assumption? > > > > I'm seeing about 140MB/s on a newer system as well. So wasn't sure if > > it's the hba or Linux or bareos or something else. > > > > On Thursday, April 10, 2025 at 9:07:41 AM UTC-5 Bruno Friedmann (bruno- > > at-bareos) wrote: > > > > Hi Jon, > > > > The encryption key is set by drive/tape so of course it is not just > > copy that block from here to here, it has to be deciphered > > uncompressed and then goes the inverse. > > From my maths (if correct) it look like you have 142MB/s read/write > > which is ~50% of native speed. > > Maybe the hba is somewhat limited and can handle more than the > > native 300MB/s one way? > > > > On Thursday, 10 April 2025 at 15:16:50 UTC+2 Jon Schewe wrote: > > > > I have 2 LTO-8 drives and I'm executing a copy job from one to > > the other. I'm using hardware encryption and compression. I have > > spooling turned off because it's tape to tape, so I woudl expect > > one could just read from one tape and write to the other. The > > source tape has 16TB of raw data. I would expect a tape to tape > > copy to be reasonably fast, however I'm finding that after 24 > > hours I've only seen 12TB copied between the 2 tapes. > > Is this just how slow the tapes are? Or is there something I can > > reconfigure in bareos to speed this up? > > > > -- > > You received this message because you are subscribed to the Google > > Groups "bareos-users" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to bareos-users...@googlegroups.com <mailto:bareos- > > users+un...@googlegroups.com>. > > To view this discussion visit https://groups.google.com/d/msgid/bareos- > > users/22318893-035d-4d10-9f52-e45906bed9e3n%40googlegroups.com > <https:// > > groups.google.com/d/msgid/bareos-users/22318893-035d-4d10-9f52- > > e45906bed9e3n%40googlegroups.com?utm_medium=email&utm_source=footer>. > > -- > Andreas Rogge andrea...@bareos.com > Bareos GmbH & Co. KG Phone: +49 221-630693-86 <+49%20221%2063069386> > http://www.bareos.com > > Sitz der Gesellschaft: Köln | Amtsgericht Köln: HRA 29646 > Komplementär: Bareos Verwaltungs-GmbH > Geschäftsführer: Stephan Dühr, Jörg Steffens, Philipp Storz > > -- You received this message because you are subscribed to the Google Groups "bareos-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to bareos-users+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/bareos-users/90608360-ba23-468e-b96e-a940ba657e09n%40googlegroups.com.
