On Monday 09 January 2006 21:49, Chris Hunter wrote:
> >> Some questions:
> >> i) Can you please post your bacula-sd.conf & bacula-dir.conf settings
> >> for LTO drives (especially HP Ultrium-1 drives) plus additional st
> >> options ?
> >
> >Even though I don't operate any LTO drives here - you should supply the
> >versions of Bacula used and OS details. Otherwise, most of what other
> >people might send will not be very useful for you.
>
> Thanks for your reply,
>
> I am using bacula 1.38.2 which I compiled from source. I am using
> Scientific Linux 4.2, which similar to CentOS, is built on rhel4 source
> binaries.
>
> I have had partial sucess with the "btape fill command". I issued the
> follwing mt commands before starting btape:
>
> mt -f /dev/nst1 rewind
> mt -f /dev/nst1 stoptions buffer-writes async-writes read-ahead
> mt -f /dev/nst1 defblksize 0
>
> Using these commands, I can run "btape fill" without errors. It writes
> ~105GB to tape in 20hrs...that's less then 2mb/s ! I think the transfer
> rate should be closer to 15Mbyte/s.
>
> Note that btape thinks the rate is ~1500KB/s (ie 15MB/s). But the drive
>
> spends most of its time idle:
> >> Wrote blk_block=5000, dev_blk_num=4999 VolBytes=322,495,472 rate=1528.4
> >> KB/s
> >> Wrote blk_block=10000, dev_blk_num=9999 VolBytes=645,055,424
>
> rate=1532.2
>
> >> KB/s
> >> Wrote blk_block=15000, dev_blk_num=14999 VolBytes=967,615,368
> >> rate=1531.0 KB/s
> >
> >I don't know the reasons, but I suspect there is definitely something
> >wrong - the data transfer is much too slow for a LTO device. 1.5
> >MBytes/second is really too slow. LTO-1 should write with much higher
> >speeds.
> >
> >I suspect a SCSI problem, something like faulty termination, wrong
> >cables and resulting slower transfers than possible, or a too high
> >simultaneous use of the SCSI bus, for example because you've got your
> >disks attached to it, too.
>
> The autochanger is the only device on the scsi bus. Next step will be
> test termination & lvd cables :(
Something is definitely wrong with your drive. A rate of 15000KB/sec is
reasonable for an LTO
drive. I have an LTO-2 drive that I just tested with btape on 1.38.4.
The only difference from the 1.38.2 version is I added a bit of timing code and
spaced
the EOF out to approx 2GB rather than 1GB, which corresponds better to Bacula's
default.
My results are:
23:31:54 Begin writing Bacula records to tape ...
...
Wrote blk_block=290000, dev_blk_num=2000 VolBytes=18,708,412,456 rate=20973.6
KB/s
Wrote blk_block=295000, dev_blk_num=7000 VolBytes=19,030,972,408 rate=21005.5
KB/s
Wrote blk_block=300000, dev_blk_num=12000 VolBytes=19,353,532,352 rate=21059.3
KB/s
Wrote blk_block=305000, dev_blk_num=1500 VolBytes=19,676,092,296 rate=21021.5
KB/s
Wrote blk_block=310000, dev_blk_num=6500 VolBytes=19,998,652,248 rate=20984.9
KB/s
Wrote blk_block=315000, dev_blk_num=11500 VolBytes=20,321,212,192 rate=21014.7
KB/s
Wrote blk_block=320000, dev_blk_num=1000 VolBytes=20,643,772,144 rate=20979.4
KB/s
...
btape: btape.c:2335 End of tape 31:0. VolumeCapacity=21,474,880,104. Write rate
= 20869.7 KB/s
23:49:03 Done filling tape at 31:0. Now beginning re-read of tape ...
And it wrote 21.474 GB in 17min 9 seconds, which works out to about 20.867
MB/sec by
my calculations, and that corresponds to the rates shown above by btape. This
is pretty reasonable
IMO because btape is in fact writing "records" to blocks as Bacula does, then
writing the blocks to
tape. The records are generated by starting with random data from /dev/random,
then for each
record (32K if I remember right), it passes through the record one byte at a
time adding the next
byte so that each record is "mixed" a bit from the previous one. Even though I
have
compression turned on, this "randomizing" the data prevents the drive from
doing any significant compression.
Note, I set "Maximum Volume Size = 20GB" so I wouldn't have to wait for the
full 200-400 GB
to be written to the tape ...
You might try turning off compression on your drive and see if that makes any
difference.
--
Best regards,
Kern
(">
/\
V_V
-------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc. Do you grep through log files
for problems? Stop! Download the new AJAX search engine that makes
searching your log files as easy as surfing the web. DOWNLOAD SPLUNK!
http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click
_______________________________________________
Bacula-users mailing list
Bacula-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bacula-users
