Thomas Mueller schrieb: > > >> > With > >> > > >> > Maximum File Size = 5G > >> > Maximum Block Size = 262144 > >> > Maximum Network Buffer Size = 262144 > >> > > >> > I get up to 150M MB/s while despooling to LTO-4 drives. Maximum File > >> > Size gave me some extra MB/s, I think it's as important as the > >> > Maximum Block Size. > >> > > >> > > >> thanks for providing this hints. just searching why my lto-4 is writing > >> just at 40mb/s. will try them out! > >> > >> searching the "Maximum File Size" in the manual I found this: > >> > >> If you are configuring an LTO-3 or LTO-4 tape, you probably will want > >> to set the Maximum File Size to 2GB to avoid making the drive stop to > >> write an EOF mark. > >> > >> 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.
That's strange. Bacula shouldn't stop writing, if the Max File Size is reached it writes a EOF marker and then continuous writing to the next file. Have you activated attribute spooling? Bacula should then only write to the DB at the end of a job. I've never used iotop but with dstat I see a more or less constant stream from the spool disks to the tape drive. If this is an HP drive, I would start with the HP LTT tool and a Media and Drive Assessment Test. There is also an performance test. This helped me several times to identify bad drives or tapes. http://h18000.www1.hp.com/products/storageworks/ltt/index.html There are only RPMs for linux, but with alien you can generate a deb package for debian if you need. I run the tests in CLF mode (command line). Ralf ------------------------------------------------------------------------------ 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
