using nmon with PowerPath on AIX

Question

how can I check how are the logical adapters configured/associated with the physical hba adapter on the AIX? These are the physical hba adapter: fcs2 U7311.D20.10C223A-P1-C07-T1 FC Adapter fcs7 U7311.D20.10C222A-P1-C03-T1 FC Adapter fscsi2 U7311.D20.10C223A-P1-C07-T1 FC SCSI I/O Controller Protocol fscsi7 U7311.D20.10C222A-P1-C03-T1 FC SCSI I/O Controller Protocol when I run nmon, I only see IOs going through 1 HBA Adapter and not showing fcs2. any ideas? ??nmon-v10r???L=LargePageStats???Host=AIXTSM9????? ???Refresh=2 secs???11:01.09?? ??Adapter-I/O-Statistics?????????????????????????? ?????????????????????????????? ?Name %busy read write xfers Disks Adapter-Type ? ?fscsi7 0.0 72546.6 0.0 KB/s 283.8 72 FC SCSI I/O Controlle? ?fscsi2 0.0 72546.6 0.0 KB/s 283.8 72 FC SCSI I/O Controlle? ?ide0 0.0 0.0 0.0 KB/s 0.0 1 ATA/IDE Controller De? ?fcs7 0.0 145093.3 0.0 KB/s 567.6 18 FC Adapter ? ?sisscsia0 0.0 0.0 0.0 KB/s 0.0 4 PCI-X Dual Channel Ul? ?sisscsia1 0.0 0.0 0.0 KB/s 0.0 4 PCI-X Dual Channel Ul? ?TOTALS 6 adapters 290186.5 0.0 KB/s 1135.3 171 TOTAL(MB/s)(3.4 ? ?????????????????????????????????????????????????? ?????????????????????????????? 'There is a bug in PowerPath on AIX that reports I/O only on one adapter with AIX tools like nmon but in fact I/O is distributed equally accross all HBAs' Can someone confirm this? My AIX server is 5.3.0.54 - AIX Kernel Version And running PowerPath: EMC powermt for PowerPath (c) Version 4.5.1 (build 19) Thanks!

dynamox · Answer

have you tried to run powermt display every=10 ...it will refresh every 10 seconds and show you any IO going accross HBAs.

emcers · Answer

In the PowerPath for AIX v4.5 Admin Guide, page 71 references the similar behavior using iostat -a command.

Conor · Answer

There are two possible explanations...What kind of array are you connected to? Is it a CLARiiON (active/passive) or Symm (active/active) array?Secondly, it may seem that the IO is only going down one path due to PowerPath's 'sticky-path' principle - The algorithm will try to use the path previously chosen for IO against the same device... as long as the load on this paths is not too high, only when the load becomes high does PowerPath actually step in and perform the load balancing.

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