high queued -i/o's in powermt output

Sounds like you answered you own question.  The FA utilization is high, so adding more FA CPUs (not just ports) will most likely reduce the queues.

Hello,

   Just to also add thats queued I/O's are historic as well. If they are stable at 14 and not incrementing they may indicate that there was an issue at one time, but not necessarily now.

The queued I/Os counter is only cleared at reboot when it is returned to zero.

Hope this helps,

   Nollaig

Quincy56,

wouldn't high FA utilization affect all devices in that case and not just one ?

Nollaig,

are you talking about PowerPath "Stats Q-IOs" counter ?

I am assuming all the devices do not have the same IO rate.  The devices with low IO rates won't show high queues.

That disk(0100) is a transaction log disk which is experiencing slow writes. The remaining disks have very less I/O or no I/O at all. The Queued I/O's on this Particular transaction log disk is varying from time to time and they are not able to process transactions fastly. So, can anyone tell me how to  minimize this effect. Will adding FA's help me to improve the perfromance or there any other ways for better perfromance for that particular drive (0100).

So it appears that a particular device is singled out and can focus there. What is different about this device than the others..? Is it a quorum device..? Did this just start happening and the only occurance..? Also, you can set "throttling-related" values per device, see: "PowerPath CLI and System Messages Reference Guide". In addtition, can also use powermt display with arguments (ex: powermt display dev=<> every=<>), to watch in intervals.. I know that powermt restore clears "historical errors" but unable to conclude this will help with queued I/O, due to being 'real time'. As Nolliag stated, need to see if these values change while being monitored...

Hello,

  Sorry Dynamox, just saw query. Looks like possible issue has been nailed down now.

Thanks again!

   Nollaig

I decided to add two more FA's for the existing windows cluster. But I need some confirmation on the FA port settings. This is what we have at present on

on 8c:1 which is conencted to the cluster

SCSI Flags
            {
              Negotiate_Reset(N)           : Disabled
              Soft_Reset(S)                : Disabled
              Environ_Set(E)               : Disabled
              HP3000_Mode(B)               : Disabled
              Common_Serial_Number(C)      : Enabled
              Disable_Q_Reset_on_UA(D)     : Disabled
              Sunapee(SCL)                 : Disabled
              Siemens(S)                   : Disabled
              Sequent(SEQ)                 : Disabled
              Avoid_Reset_Broadcast(ARB)   : Disabled
              Server_On_AS400(A4S)         : Disabled
              SCSI_3(SC3)                  : Enabled
              SPC2_Protocol_Version(SPC2)  : Enabled
              SCSI_Support1(OS2007)        : Disabled
            }

The other FA (8a:1)which  we thought of adding to the cluster has the below settings

SCSI Flags
            {
              Negotiate_Reset(N)           : Disabled
              Soft_Reset(S)                : Disabled
              Environ_Set(E)               : Disabled
              HP3000_Mode(B)               : Disabled
              Common_Serial_Number(C)      : Enabled
              Disable_Q_Reset_on_UA(D)     : Disabled
              Sunapee(SCL)                 : Disabled
              Siemens(S)                   : Disabled
              Sequent(SEQ)                 : Disabled
              Avoid_Reset_Broadcast(ARB)   : Disabled
              Server_On_AS400(A4S)         : Disabled
              SCSI_3(SC3)                  : Enabled
              SPC2_Protocol_Version(SPC2)  : Disabled
              SCSI_Support1(OS2007)        : Disabled
            }

Can any one confirm if i can go ahead and use 8a:1 and 9a:1 as additional FA's for the windows cluster. SPC2 bit is different on both .

what version of windows ?

If we set via hba_flags do we need to reboot the cluster in order to take effect the settings. 

or you can drop the zone from that host to the new FAs

Message was edited by: dynamox

These are the Windows cluster details..