Hi Mike,

Is bs=128K a linux, iscsi or IBM parameter?

Thanks,
Simone
 

> -----Original Message-----
> From: open-iscsi@googlegroups.com [mailto:open-is...@googlegroups.com] On
> Behalf Of Mike Christie
> Sent: Thursday, April 09, 2009 10:55 AM
> To: open-iscsi@googlegroups.com
> Subject: Re: Open iSCSI Performance on IBM
> 
> 
> Gonçalo Borges wrote:
> > Hi All...
> >
> > Sorry, the following could be a little bit off topic...
> >
> > Does any one has an idea of what is the expected performance for a IBM
> > DS 3300 system connected via open iSCSI? Using a RAID 1 with 2 disks,
> > I got the following numbers:
> >
> 
> Is /apoio04/b1 a scsi/iscsi disk or is it LVM/DM/RAID on top of a
> iscsi/scsi disk?
> 
> Could you set the IO scheduler to noop
> echo noop > /sys/block/sdX/queue/scheduler
> 
> and see if that makes a difference.
> 
> Also try
> 
> bs=128k
> 
> And then also run
> iscsiadm -m session -P 3
> 
> 
> 
> > Sequential Write:
> >
> >  [r...@core12 ~]# dd if=/dev/zero of=/apoio04/b1 bs=64k count=125000
> > 125000+0 records in
> > 125000+0 records out
> > 8192000000 bytes (8.2 GB) copied, 454.522 seconds, 18.0 MB/s
> >
> > Sequential Read:
> > [r...@core12 ~]# dd if=/apoio04/b1 of=/dev/null bs=64k count=125000
> > 125000+0 records in
> > 125000+0 records out
> > 8192000000 bytes (8.2 GB) copied, 94.9401 seconds, 86.3 MB/s
> >
> > I restricted the RAM to be only 1GB, therefore there are no cache
> > effects in these numbers. Because the read stats are good, we exclude
> > network bottlenecks. Nevertheless, we were expecting more or less the
> > performance of a single disk (~50MB/s) for the write tests and we are
> > getting less than half. I do not know if this is really the physical
> > limit of the system or if there is a problem somewhere...
> >
> > I could not find any IBM official numbers, therefore, I though that
> > someone over here could give me any hint about the numbers they are
> > getting...
> >
> > Thanks in Advance
> > Cheers
> > Goncalo Borges
> > >
> 
> 
> 

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