[Stgt-devel] Performance of SCST versus STGT

[Bart Van Assche]

On Jan 22, 2008 4:26 AM, FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp> wrote:
>
> First, I recommend you to examine iSER stuff more since it has some
> parameters unlike SRP, which effects the performance, IIRC. At least,
> you could get the iSER performances similar to Pete's.

Apparently open-iscsi uses the following defaults:
node.session.iscsi.FirstBurstLength = 262144
node.session.iscsi.MaxBurstLength = 16776192
node.conn[0].tcp.window_size = 524288
node.conn[0].iscsi.MaxRecvDataSegmentLength = 131072

I have tried to change some of these parameters to a larger value, but
this did not have a noticeable effect (read bandwidth increased less
than 1%):
$ iscsiadm --mode node --targetname
iqn.2007-05.com.example:storage.disk2.sys1.xyz --portal
192.168.102.5:3260 --op update -n node.session.iscsi.FirstBurstLength
-v 16776192
$ iscsiadm --mode node --targetname
iqn.2007-05.com.example:storage.disk2.sys1.xyz --portal
192.168.102.5:3260 --op update -n node.session.iscsi.MaxBurstLength -v
16776192
$ iscsiadm --mode node --targetname
iqn.2007-05.com.example:storage.disk2.sys1.xyz --portal
192.168.102.5:3260 --op update -n
"node.conn[0].iscsi.MaxRecvDataSegmentLength" -v 16776192

Bart.