[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Bacula-devel] MaximumBlockSize Problem and Question


On Wed, 2008-11-05 at 13:34 +0200, Pasi Kärkkäinen wrote:
> On Wed, Nov 05, 2008 at 11:12:01AM +0100, Ulrich Leodolter wrote:
> > Hello,
> > 
> > Problem:
> > 
> > Settings like (documented in the Manual)
> > 
> >      Minimum block size = 64K
> >      Maximum block size = 200K
> > 
> > do not work. Both are defined as size_pint32.
> > multipliers like K M are not allowed.
> > don't know if this is intended, 
> > maybe documentation just a little outdated.
> > 
> > 
> > Question:
> > 
> > Can i expect performance improvements (especially for
> > Copy/Migrate Disk to Tape jobs) by by increasing
> > "Maximum block size" on File devices in bacula-sd.conf ???
> > 
> > Device {
> >   Name = FileStorage
> >   Media Type = File
> >   Archive Device = /disk0/bacula/files
> >   LabelMedia = yes;  
> >   Random Access = Yes;
> >   Requires Mount = No;
> >   AutomaticMount = yes;
> >   RemovableMedia = no;
> >   AlwaysOpen = no;
> >   MaximumBlockSize = 1048576;         # 1M
> > }
> > 
> 
> I think it should make difference at least with tape drives.. 
> 
> You can measure the difference with dd:
> 
> dd if=/dev/null of=/dev/tape bs=<try_different_block_sizes_here>
> 
> 4k, 64k, 256k, 1MB, 4MB etc.

Hello,

I dont think raw performance is bad, as u can see below
(exeption is 4k block size on tape,
 hopfully bacula does not use it :-)

Maybe i should set

	Minimum Block Size = 4194304

on both devices (Tape, File)
This should reduce the number of block read/writes communication
by a factor of 64.

Will try it tonight,  unless u give me a very good hint how to
optimize ;-)

BR
Ulrich

---++ Raw Tape Performance

[root@troll ~]# dd if=/dev/zero of=/dev/nst1 bs=4k count=256k
262144+0 records in
262144+0 records out
1073741824 bytes (1.1 GB) copied, 48.2057 seconds, 22.3 MB/s

[root@troll ~]# dd if=/dev/zero of=/dev/nst1 bs=64k count=64k
65536+0 records in
65536+0 records out
4294967296 bytes (4.3 GB) copied, 41.4204 seconds, 104 MB/s

[root@troll ~]# dd if=/dev/zero of=/dev/nst1 bs=256k count=16k
16384+0 records in
16384+0 records out
4294967296 bytes (4.3 GB) copied, 34.1308 seconds, 126 MB/s

[root@troll ~]# dd if=/dev/zero of=/dev/nst1 bs=1024k count=4k
4096+0 records in
4096+0 records out
4294967296 bytes (4.3 GB) copied, 32.3195 seconds, 133 MB

[root@troll ~]# dd if=/dev/zero of=/dev/nst1 bs=4096k count=4k
4096+0 records in
4096+0 records out
17179869184 bytes (17 GB) copied, 119.205 seconds, 144 MB/s

---++ Raw SATA Raid Performance

[root@troll ~]# dd if=/dev/zero of=/disk0/test.img bs=4k count=4096k
4194304+0 records in
4194304+0 records out
17179869184 bytes (17 GB) copied, 83.0424 seconds, 207 MB/s

[root@troll ~]# dd if=/dev/zero of=/disk0/test.img bs=64k count=256k
262144+0 records in
262144+0 records out
17179869184 bytes (17 GB) copied, 81.8973 seconds, 210 MB/s

> 
> -- Pasi

-- 
Ulrich Leodolter <ulrich.leodolter@xxxxxxxx>
OBVSG


-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
Bacula-devel mailing list
Bacula-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/bacula-devel


This mailing list archive is a service of Copilotco.