Question about Best Practice Active-Active

[To-M]

These are the recommended VMware iSCSI target settings, the performance increase is very difficult to give an exact number but if you test with the defaults to these settings you should see an increase.

[Toni Bizjak]

...not to open new thread:

We are planning to combine two separate DSS7 iSCSI targets:
- one for VMWare ESXi initiators with parameters (recomended above)
maxRecvDataSegmentLen=262144
MaxBurstLength= 1048576
Maxxmitdatasegment=262144
FirstBurstLength=65536
DataDigest=None
maxoutstandingr2t=8
InitialR2T=No
ImmediateData=Yes
headerDigest=None
(deprecated)Wthreads=8

- and another one for native Win initiators (cluster of 2x Server2008R2)

Is it better to use default parameters on Win and adjust particular target on DSS7?
DelayBetweenReconnect=5
EnableNOPOut=0
ErrorRecoveryLevel=2
FirstBurstLength=#00010000=65536
ImmediateData=1
InitialR2T=0
IPSecConfigTimeout=#0000003c=60
LinkDownTime=#0000000f=15
MaxBurstLength=#00040000=262144
MaxConnectionRetries=#ffffffff
MaxPendingRequests=#000000ff
MaxRecvDataSegmentLength=#00010000=65536
MaxRequestHoldTime=#0000003c=60
MaxTransferLength=#00040000=262144
NetworkReadyRetryCount=#0000000a=10
PortalRetryCount=#00000005=5
SrbTimeoutDelta=#0000000f=15
TCPConnectTime=#0000000f=15
TCPDisconnectTime=#0000000f=15
WMIRequestTimeout=#0000001e=30

or adjust "VMWare recomend" parameters to Windows iSCSI initiator?

Thank you for the answer!
Toni

[Gr-R]

If you change target values, you will also need to adjust windows initiator.

[gharding]

Why not create multiple iscsi targets, then the targets for windows initiator set them according the windows settings and the targets for vmware set them to match vmware. The settings in open-e are per target and not global I believe

[Toni Bizjak]

This is the point of my question:

Is it recomended to adjust target settings to initiator defaults?

Default iSCSI settings are different between VMWare, Server2008 and DSS7
(can't find recomended maxoutstandingr2t=? for Win).
Can you recomend propriate settings on DSS console for WinServer2008R2, for example?

Is performance better, if all targets&initiators use equally settings?

Thank you for the answer!
Toni

[gharding]

I would say adjust the targets to match the initiator settings, open-e's target setting s are standard generic that will work by default, but the other vendors have set their initiators for best performance for there OS. Also remember that on VMware if using round robin to set the IOPS setting to 1 for the volumes.

[Toni Bizjak]

DelayBetweenReconnect=5
EnableNOPOut=0
ErrorRecoveryLevel=2
FirstBurstLength=#00010000=65536
ImmediateData=1
InitialR2T=0
IPSecConfigTimeout=#0000003c=60
LinkDownTime=#0000000f=15
MaxBurstLength=#00040000=262144
MaxConnectionRetries=#ffffffff
MaxPendingRequests=#000000ff=255 - maxoutstandingr2t?
MaxRecvDataSegmentLength=#00010000=65536
MaxRequestHoldTime=#0000003c=60
MaxTransferLength=#00040000=262144 - Maxxmitdatasegment?
NetworkReadyRetryCount=#0000000a=10
PortalRetryCount=#00000005=5
SrbTimeoutDelta=#0000000f=15
TCPConnectTime=#0000000f=15
TCPDisconnectTime=#0000000f=15
WMIRequestTimeout=#0000001e=30

Can I also tune MPIO round robin IOPS setting in Server2008?