Re: [Iscsitarget-devel] OT: IO Performance on Server

[Roland K. <rol...@in...>]

----- Ursprüngliche Mail -----
Von: "Luca Berra" <bl...@co...>
An: isc...@li...
Gesendet: Samstag, 27. November 2010 18:10:57
Betreff: Re: [Iscsitarget-devel] OT: IO Performance on Server

On Sat, Nov 27, 2010 at 02:26:29PM +0100, Roland Kaeser wrote:
>> > > installed a DRBD Cluster with ISCSI Cluster Interface on two really
>> > > powerful machines: - Xeon E5506
>> > > - 4GB Ram
>> > > - Adaptec 5805 Raid controller
>> > > - 8x WD 1TB HD
my concept of very powerful is a littel bit different than yours

>The Problem ist that the filesystem above (XenServer 5.6 through iSCSI uses 512byte blocksizes) which is therefore limited to the 100MB/s speed.  So the primary question is how can I get the thoughput of this 580MB/s or values around 400-500MB/s with 512Byte blocksize.

>filesystem block size does not equal io-size

>L.

>-- 
>Luca Berra -- bl...@co...

Does the io-size differ from 

/sys/block/sdb/queue/hw_sector_size, 
/sys/block/sdb/queue/logical_block_size
and 
/sys/block/sdb/queue/physical_block_size

and where is it defined? On my system the values are:

/sys/block/sdb/queue/hw_sector_size = 512
/sys/block/sdb/queue/logical_block_size = 512
/sys/block/sdb/queue/minimum_io_size = 512
/sys/block/sdb/queue/physical_block_size = 512

blockdev --setbsz 4096 /dev/sdb does not change anything.

Regards

Roland