Thomas Mueller wrote: >>> maybe this is the reason for the "extra mb/s". >> Modifying the Maximum Block Size to more than 262144 didn't change much >> here. But changing the File Size did. Much. > > I found a post from Kern saying that Quantum told him, that about 262144 > is the best blocksize - increasing it would increase error rate too. > >> Anyway, 40 MB/s seems a bit low, even with the defaults. Before tuning >> our setup I got ~75 MB/s. Are you spooling the data to disk or writing >> directly to tape? > > yes, i was surprised too that it is that slow. > > I'm spooling to disk first (2x 1TB disk as RAID0, dedicated to bacula for > spooling). i will also start a sequential read test to check if the disks > are the bottleneck. The slow job was the only one running. > > watching iotop i saw the "maximum file size" problem: it stops writing > after 1 GB (default file size) and writes to the DB and then continues > writing. so for a LTO-4 it stops nearly 800 times until the tape is full.
I've also increased the Maximum File Size, I'm spooling of a ram-disk to LTO4 tapes seeing rates like this: 04-Jan 23:09 bacula-sd JobId 33739: Despooling elapsed time = 00:01:22, Transfer rate = 121.9 M bytes/second 04-Jan 23:15 bacula-sd JobId 33739: Despooling elapsed time = 00:01:24, Transfer rate = 119.0 M bytes/second 04-Jan 23:21 bacula-sd JobId 33739: Despooling elapsed time = 00:01:24, Transfer rate = 119.0 M bytes/second 04-Jan 23:26 bacula-sd JobId 33739: Despooling elapsed time = 00:01:21, Transfer rate = 123.4 M bytes/second 04-Jan 23:31 bacula-sd JobId 33739: Despooling elapsed time = 00:01:25, Transfer rate = 117.6 M bytes/second 04-Jan 23:40 bacula-sd JobId 33734: Despooling elapsed time = 00:01:06, Transfer rate = 151.5 M bytes/second 04-Jan 23:46 bacula-sd JobId 33734: Despooling elapsed time = 00:00:56, Transfer rate = 178.5 M bytes/second 04-Jan 23:53 bacula-sd JobId 33734: Despooling elapsed time = 00:01:00, Transfer rate = 166.6 M bytes/second 04-Jan 23:57 bacula-sd JobId 33734: Despooling elapsed time = 00:00:57, Transfer rate = 175.4 M bytes/second 05-Jan 00:02 bacula-sd JobId 33734: Despooling elapsed time = 00:01:02, Transfer rate = 161.2 M bytes/second 05-Jan 00:08 bacula-sd JobId 33734: Despooling elapsed time = 00:01:00, Transfer rate = 166.6 M bytes/second 05-Jan 00:12 bacula-sd JobId 33734: Despooling elapsed time = 00:00:52, Transfer rate = 192.3 M bytes/second 05-Jan 00:17 bacula-sd JobId 33734: Despooling elapsed time = 00:00:59, Transfer rate = 169.4 M bytes/second 05-Jan 00:22 bacula-sd JobId 33734: Despooling elapsed time = 00:00:58, Transfer rate = 172.4 M bytes/second 05-Jan 00:29 bacula-sd JobId 33734: Despooling elapsed time = 00:00:58, Transfer rate = 172.4 M bytes/second 05-Jan 00:37 bacula-sd JobId 33734: Despooling elapsed time = 00:00:58, Transfer rate = 172.4 M bytes/second On LTO3 tapes in the LTO4 drive it tops at around 120MB/s. -- Jesper ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users