Sorry for answering again, accidently hit send while not finished to compare an LTO4 drive with an Ultra320 controller I get around 55MB/sec
my guess is that the LTO3 drive should deliver around 30-40MB/sec with the right controller (ultra320). (pay note to that there usually are 2 models, a fast and slow one, from each vendor) trying to remember back when using a 2940UW host adapter with a UW drive. I seem to remember to get around 10MB/sec out of the drive so 8.8MB/sec does seem like it's what you can get out of the controller. (I could remember wrong) cheers Carsten On 2012-10-18 21:02, Wolfgang Denk wrote: > Hello, > > apologies in advance - this may be a bit off topic, but I guess I find > most experts for such a problem on this list... > > > I see very poor performance with HP Ultrium LTO3 drive, which is > attached over SCSI to a Linux box (using a Adaptec 2940 Ultra SCSI > adapter). It seems I cannot get more than about 8.8 MBytes/s for > either writing to or reading from the drive. > > Looking around, I see this information in /proc/scsi/aic7xxx/3 : > > ... > Target 5 Negotiation Settings > User: 40.000MB/s transfers (20.000MHz, offset 127, 16bit) > Goal: 10.000MB/s transfers (10.000MHz, offset 15) > Curr: 10.000MB/s transfers (10.000MHz, offset 15) > Channel A Target 5 Lun 0 Settings > Commands Queued 20 > Commands Active 0 > Command Openings 1 > Max Tagged Openings 4 > Device Queue Frozen Count 0 > ... > > Am I understanding this correctly that the SCSI adapter is set to > 10 MB/s transfers only? That would certainly expolain the transfer > rates I'm observing... > > Is there any way to tweak these settings in Linux? I alreay checked > in the SCSI adapter's BIOS settings, but there are no indications for > auch a limitation. > > [Yes, I am aware that the Adaptec 2940 is not exactly new. But I > should get more than 8.8 MB/s out of it, should I not?] > > Any help welcome. Thanks in advance. > > Best regards, > > Wolfgang Denk > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
