Re: [Iscsitarget-devel] iet and open-iscsi deadlock

[Ming Z. <mi...@el...>]

* open-iscsi has newer code, u can get from
svn://svn.berlios.de/open-iscsi

* we need more information about the HW configuration of your boxes.

* how you produce large # of parallel r/w and can you reproduce this
every time.

* some of your description looks at ini side, some are target side.
pretty mixed. so it is quite hard to understand. when u mention fopen,
it is ini side? then iowait 60-70%, it is ini or target side?

ming


On Thu, 2006-03-09 at 22:18 -0500, Jeff Hardy wrote:
> I have iscsitarget-0.4.13 exporting some block devices to a box running
> open-iscsi-1.0-485.  Both boxes are running linux-2.6.14.6.  I have done
> all kinds of read and write tests and gotten great performance with scsi
> exports, AoE exports, RAID exports, lvm exports, etc.
> 
> However I am having a problem when I do lots of parallel writes on a
> volume.  Many of the processes end up in the 'D' state for lengthy
> periods of time, and with lots of parallel reads and writes (thousands)
> I can often overburden things to the point where things just grind to a
> halt.
> 
> Here are my iet settings for each of the volumes:
> 
> InitialR2T=No
> ImmediateData=Yes
> MaxConnections=1
> MaxRecvDataSegmentLength=8192
> MaxXmitDataSegmentLength=8192
> MaxBurstLength=262144
> FirstBurstLength=65536
> DefaultTime2Wait=2
> DefaultTime2Retain=0
> MaxOutstandingR2T=1
> DataPDUInOrder=Yes
> DataSequenceInOrder=Yes
> ErrorRecoveryLevel=0
> HeaderDigest=None
> DataDigest=None
> OFMarker=No
> IFMarker=No
> OFMarkInt=Reject
> IFMarkInt=Reject
> Wthreads        16
> 
> 
> On the open-iscsi side:
> 
> node.transport_name = tcp
> node.tpgt = 1
> node.active_conn = 1
> node.startup = manual
> node.session.initial_cmdsn = 0
> node.session.reopen_max = 32
> node.session.auth.authmethod = None
> node.session.auth.username = <empty>
> node.session.auth.password = <empty>
> node.session.auth.username_in = <empty>
> node.session.auth.password_in = <empty>
> node.session.timeo.replacement_timeout = 0
> node.session.err_timeo.abort_timeout = 10
> node.session.err_timeo.reset_timeout = 30
> node.session.iscsi.InitialR2T = No
> node.session.iscsi.ImmediateData = Yes
> node.session.iscsi.FirstBurstLength = 262144
> node.session.iscsi.MaxBurstLength = 16776192
> node.session.iscsi.DefaultTime2Retain = 0
> node.session.iscsi.DefaultTime2Wait = 0
> node.session.iscsi.MaxConnections = 0
> node.session.iscsi.MaxOutstandingR2T = 1
> node.session.iscsi.ERL = 0
> node.conn[0].address = 10.10.0.1
> node.conn[0].port = 3260
> node.conn[0].startup = manual
> node.conn[0].tcp.window_size = 524288
> node.conn[0].tcp.type_of_service = 0
> node.conn[0].timeo.login_timeout = 15
> node.conn[0].timeo.auth_timeout = 45
> node.conn[0].timeo.active_timeout = 5
> node.conn[0].timeo.idle_timeout = 60
> node.conn[0].timeo.ping_timeout = 5
> node.conn[0].timeo.noop_out_interval = 0
> node.conn[0].timeo.noop_out_timeout = 0
> node.conn[0].iscsi.MaxRecvDataSegmentLength = 131072
> node.conn[0].iscsi.HeaderDigest = None,CRC32C
> node.conn[0].iscsi.DataDigest = None
> node.conn[0].iscsi.IFMarker = No
> node.conn[0].iscsi.OFMarker = No
> 
> 
> 
> I can only say it seems to be a concurrency issue, with lots going on on
> the volume.  Even with just a few hundred random read or write ops, just
> requesting an fopen() can take several seconds. Overall processor load
> (2 processors) is low but wait states run 60-70%.  Doubling the Wthreads
> value seems to have helped a bit.  Is there anything I am missing that
> might help with this?
> 
> 
> 
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