On Tue, Nov 04, 2008 at 10:21:54PM +0100, Ulrich Leodolter wrote:
> 
> On Tue, 2008-11-04 at 22:38 +0200, Pasi Kärkkäinen wrote:
> > On Tue, Nov 04, 2008 at 09:02:46PM +0100, Ulrich Leodolter wrote:
> > > Hi,
> > > 
> > > Problem:  Migrate/Copy jobs from disk pool (DiskBackup)
> > > to tape (DiskCopy) only get overall speed of 10-20MB/s.
> > > 
> > > full backup job size varies from 10-50GB.
> > > 
> > > Pool setup is simple, just one pool for full an incremental backups
> > > to disk (automatic recycle works good)
> > > 
> > > Pool {
> > >   Name = DiskBackup
> > >   Pool Type = Backup
> > >   Recycle = yes
> > >   RecyclePool = DiskBackup
> > >   AutoPrune = yes
> > >   Volume Retention = 15 days
> > >   Volume Use Duration = 6 days
> > >   Maximum Volume Bytes = 4G
> > >   Label Format = Backup-
> > >   Next Pool = DiskCopy
> > > }
> > > 
> > > DiskCopy pool goes to LTO4 tape device.
> > > DiskBackup goes to SATA external raid (6T ext3).
> > >
> > 
> > Which raid-level your SATA external raid is? 
> > 
> 
> Raid 5
> >  
> > > concurrency for DiskBackup jobs is 15,  jobs are spread
> > > over DiskBackup Valumes (maybe thats the main problem)
> > > 
> > > i can read write/continuous on both devices at about 70MB/s
> > > (SATA is not fast)
> > >
> > 
> > So your SATA-raid can do max 70 MB/sec.. 
> > 
> > How much your LTO4 can do? 
> 
> 70MB/sec
>

Have you tried with dd if=/dev/null of=/dev/tape bs=<bigblocksize>
to get the actual max tape drive performance.. ?

> >  
> > > i tried spooling to local SAS raid, but overall speed is lower
> > > than direct writing to tape.
> > > despooling from SAS raid to Tape runs at Tape maximum spped.
> > >
> > 
> > So SAS-RAID to Tape is faster than SATA-RAID to Tape? 
> >  
> 
> about 180MB/s continuous write
>

Yep. Over 2x compared to SATA-Raid. 

So clearly it's the RAID that's limiting your performance.
 
> > > 
> > > 
> > > I need some Performance tuning tips, maybe:
> > > 
> > > Limit jobs per Volume in DiskBackup pools?
> > > Split DiskBackup into DiskFull and DiskIncr pools?
> > > 
> > 
> > First determine the bottleneck and then work around it.. 
> > 
> 
> Thats why i am asking :-)
> 
> i tried to monitor disk using dstat
> http://dag.wieers.com/home-made/dstat/
> i reports 70MB/s read while bacula Copy Job is running.
> 
> looks like some overhead is in bacula itself:
> 
> avg iostat while bacula CopyDiskToTape
> 
> user     9.12
> system   2.79
> iowait  17.00
> 
> avg iostat while EMC Networker (Legato) Clone Disk to Tape
> (on the same hardware)
> 
> user     2.14
> system   2.02
> iowait  12.84
> 
> as u can see user and iowait are higher for bacula.
> total Copy Jobs size is about 800GB (one LTO4 Tape)
> 
> Networker backup jobs to disk run in parallel (max 10),
> i dont think backup file sets are continous on disk.
> 

Hmm.. have you adjusted block sizes bacula uses? 

"iostat" is also useful tool.. I guess it's part of "sysstat" package.

> 
> > Btw. could you post your 'copy' job? I'm in the process of trying it out but
> > I'm still stuck with trying to implement 'copy only uncopied 
> > jobs'-feature.. 
> > 
> > -- Pasi
> > 
> 
> Job {
>   Name = "CopyDiskToTape"
>   Type = Copy
>   Client = dir-fd
>   Level = Full                  # must be defined, but is ignored
>   FileSet = "Full Set"          # must be defined, but is ignored
>   Pool = DiskBackup
>   Storage = File
>   Messages = Standard
>   Selection Type = PoolUncopiedJobs
>   Maximum Concurrent Jobs = 10
> #  SpoolData = yes
> }
> 
> 
> PoolUncopiedJobs is based on an SQLQuery i posted in the devel list.
> i am running 2.5.17 svn at the server side
> 

Oh nice, I missed that. 

I'll try it out:)

-- Pasi

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