Athanasios Douitsis schrieb: > > Hi everyone, > > Our setup consists of a Dell 2950 server (PERC6i) w/ FreeBSD7 and two HP > Ultrium LTO4 drives installed in a twin Quantum autochanger enclosure. > Our bacula version is 5.0.0 (which is the current FreeBSD port version). > > Here is our problem: > > When running a single job, our setup is able to consistently surpass > 70Mbytes/sec (or even 80) on despooling, which should be reasonably > enough. Unfortunately, when running several jobs on both drives (for > example 6+6 parallel jobs) our despooling speeds drop to about > 20Mbytes/sec or even less. The speed of the jobs to finish last > naturally ramp up, especially for the very last. Our hypothesis is that > the spooling area cannot handle simultaneous reading (from jobs that are > still tranfering) and writing (from the currently despooling job) too > well, hence the performance loss. > > So far we were using a common spool area for both drives on these two > test setups: > > 1)A spool area on a Clarion CX4 Fibre Channel array (4Gbps) w/ 2x10Krpm > disks on a raid0 configuration. > 2)A 2xSCSI320 raid0 striped configuration in the server itself (via the > PERC6i controller). > > Both setups yielded similarly poor results. > > Our thoughts/questions: > > -Should we use a separate spool area for each drive? > -Anyone else that has had problems with the despooling speed being too > low? What are your proposed solutions, if any? > > I realize this is not strictly a bacula question, however the matter > should be of interest for any bacula admin out there. I understand that > under like 40Mbytes/sec the drive constantly starts and stops, a > process which is detrimental to its expected lifetime (and the tape's > as well).
I've had the same problem. First I started with a simple 2 Disk RAID1 as spool area for our 3 LTO-4 drives. With more jobs running in parallel this was simply not enought. In the end I put 6 WD Raptor SATA drives in the server, configured a large RAID10 and limited the number of concurrent jobs to 3. Now I get ~100 MB/s for each of the 3 jobs. If you really need to run so many jobs concurrently put as many fast disks in the server as possible and configure them as RAID10. Maybe use SSD's instead of SATA/SAS Disk? Ralf ------------------------------------------------------------------------------ _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
