Re: iSCSI read/write cost difference

[mingz <mingz@ele.uri.edu>]

InitialR2T=No , ImmediateData=Yes , and i am not sure about the answer for 
last question.

under is all the values.
-----------------------------------------
../common/iscsi_manage init restore host=$1
../common/iscsi_manage init force v=1800 host=$1
../common/iscsi_manage init set 
TargetName=iqn.2002-10.edu.unh.iol.iscsi.draft18-target_$2 host=$1
../common/iscsi_manage init set 
InitiatorName=iqn.1999-11.edu.unh.iol.iscsi.draft18-initiator host=$1
../common/iscsi_manage init set InitiatorAlias=UNH-Draft18-Initiator host=$1
../common/iscsi_manage init set MaxConnections=4 host=$1
../common/iscsi_manage init set HeaderDigest=CRC32C,None host=$1
../common/iscsi_manage init set DataDigest=CRC32C,None host=$1
../common/iscsi_manage init set InitialR2T=No host=$1
../common/iscsi_manage init set ImmediateData=Yes host=$1
../common/iscsi_manage init set MaxRecvDataSegmentLength=12288 host=$1
../common/iscsi_manage init set FirstBurstLength=16384 host=$1
../common/iscsi_manage init set MaxBurstLength=32768 host=$1
../common/iscsi_manage init set OFMarker=No host=$1
../common/iscsi_manage init set IFMarker=Yes host=$1
../common/iscsi_manage init set IFMarkInt=4096~32768 host=$1
../common/iscsi_manage init set OFMarkInt=1024~8192 host=$1
../common/iscsi_manage init set DefaultTime2Wait=10 host=$1
../common/iscsi_manage init set DefaultTime2Retain=6 host=$1
../common/iscsi_manage init set MaxOutstandingR2T=4 host=$1
../common/iscsi_manage init set DataPDUInOrder=No host=$1
../common/iscsi_manage init set DataSequenceInOrder=No host=$1
../common/iscsi_manage init set ErrorRecoveryLevel=0 host=$1
../common/iscsi_manage init snack d=y host=$1
../common/iscsi_manage init snack s=y host=$1
../common/iscsi_manage init force i=2 host=$1
../common/iscsi_manage init force p=2 host=$1


On Thursday 17 April 2003 12:39, you wrote:
> What are the negotiated values of InitialR2T and ImmediateData in your
> setup? Also, does the target piggyback SCSI Response in the Final Datain
> pdu?
>
>
> -----Original Message-----
> From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> mingz
> Sent: Thursday, April 17, 2003 12:10 PM
> To: ips@ece.cmu.edu
> Subject: iSCSI read/write cost difference
>
>
> I recently did some experiments on iSCSI benchmarking. I used the UNH iSCSi
> ref18_03 implementation and use a ram based scsi device for iscsi target
> use.
> so there is no any disk overhead.
>
> I used a linux kernel module to send fixed size read/write requests to
> iscsi initiator, which eventually will be filled by iscsi target. i use
> interl pro1000 gigabit nic and intel 470 gigabit switch. and both initiator
> and target use same type piii 866 pc with 1g ram.
>
> now the IOPS result shows that
>
> 		2k		4k		8k		16k		32k
> read		1975	1781	1557	1081	767
> write 	2877	2225	1588	812		533
>
> for small reuqests, read is slower than write, while for large requests,
> read
> is faster than write. i redo the experiments on another enviroment, also
> get similar results.
>
> can anybody explain why this happens?
>
> thanks a lot.
>
>
> ming

-- 
 --------------------------------------------------
| Ming Zhang, PhD. Student                                     
| Dept. of Electrical & Computer Engineering       
| College of Engineering                           
| University of Rhode Island                       
| Kingston RI. 02881                                  
| e-mail: mingz@ele.uri.edu                        
| Tel. (401) 874-2293 Fax  (401) 782-6422          
| http://www.ele.uri.edu/~mingz                     
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