Hello,
On 1/10/2006 12:03 AM, Kern Sibbald wrote:
On Monday 09 January 2006 21:49, Chris Hunter wrote:
...
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,
That might be something to consider - some random-data sources (or
rather pseudo-random number generators - are actually *slow* This might
be something that depends on the distribution you use.
Check what btape really uses (look in the source, use strace or use
lsof, for example) and measure its speed: 'time dd if=/dev/random
of=/dev/null bs=64k count=256' for example. Try different sources for
random - /dev/randomand /dev/urandom or /dev/hwrandom might be possible
devices to use.
Just an idea.
Arno
--
IT-Service Lehmann [EMAIL PROTECTED]
Arno Lehmann http://www.its-lehmann.de
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