Hi everyone- I have an DLT-S4 drive hooked up to a Dell 1950 running CentOS and Bacula 2.0.3. Everything works just fine, but the throughput to the tape drive is really slow. After mucking around with tar, I found that increasing the block size really improves the performance of the tape drive. According to tapeinfo, the drive can handle block sizes to just under 16 MB. Using a block size close to 16 MB gives me some of that awesome speed that Quantum promised:
bash-3.00# tar -c --totals -b 32000 -f /dev/nst0 . Total bytes written: 1179648000 (1.1GiB, 94MiB/s) I went to change the Maximum block size value in my SD, but I get data overrun errors while running a job with anything larger than 512 KB. Here's some output from the SD when the block size is set to 900000: bash-3.00# /usr/sbin/bacula-sd -f -d500 .. snip ... cfile-prod-bkp-1-sd: append.c:300 back from write_end_session_label() cfile-prod-bkp-1-sd: spool.c:137 Committing spooled data cfile-prod-bkp-1-sd: spool.c:220 Despooling data cfile-prod-bkp-1-sd: device.c:345 lock 0 from spool.c:235 cfile-prod-bkp-1-sd: block.c:443 binbuf=899991 buf_len=900000 cfile-prod-bkp-1-sd: block.c:443 binbuf=899993 buf_len=900000 cfile-prod-bkp-1-sd: block.c:443 binbuf=899995 buf_len=900000 cfile-prod-bkp-1-sd: dev.c:1655 weof_dev cfile-prod-bkp-1-sd: askdir.c:395 >dird: CatReq Job=cFile1_Full.2007-06-04_11.37.16 CreateJobMedia FirstIndex=1 LastIndex=43682 StartFile=3 EndFile=3 StartBlock=0 EndBlock=1110 Copy=0 Strip=0 MediaId=20 Damaged buffers found at bnet.c:288 discovery of data overrun. Buffer address: 2a985a5010 Damaged buffer: 900016 bytes allocated at line 130 of cfile-prod-bkp-1-sd block.c 04-Jun 11:42 cfile-prod-bkp-1-sd: ABORTING due to ERROR in smartall.c:430 Damaged buffer found. Called from bnet.c:288 Kaboom! bacula-sd, cfile-prod-bkp-1-sd got signal 11. Attempting traceback. Kaboom! exepath=/usr/sbin/ cfile-prod-bkp-1-sd: signal.c:138 Working=/var/bacula cfile-prod-bkp-1-sd: signal.c:139 btpath=/usr/sbin/btraceback cfile-prod-bkp-1-sd: signal.c:140 exepath=/usr/sbin/bacula-sd Calling: /usr/sbin/btraceback /usr/sbin/bacula-sd 5335 cfile-prod-bkp-1-sd: signal.c:165 Doing waitpid With 512 KB blocks, I get around 45-50 MB/sec. This isn't bad, but I know that tape drive can do better. Using 512 KB blocks with tar gives me about the same speed as Bacula: bash-3.00# tar -c --totals -b 1024 -f /dev/nst0 . Total bytes written: 1178075136 (1.1GiB, 45MiB/s) Is anyone else seeing this problem with large block sizes? I know these faster tapes drives seem to like those bigger block sizes. =) Thanks! -Mikey -- Mikey Orr Core Technologies Unix System Administrator ITS @ University of California, Santa Cruz Call me at (831) 459-4222 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
