Originally posted by: jakub.k.wartak

Hello all, I've asked this on NetApp community forum, but still looking for answers:

I'm seeking guidance/answers. AIX 6.1TL3 here, with MPIO NetApp installed, NO ALUA, versions below:

root@x:/oracle/TPM/sapdata1# lslpp -cl|grep -i netapp
/usr/lib/objrepos:NetApp.SAN_toolkit.sanlun:5.0.0.0::COMMITTED:I:Network Appliance AN Toolkit sanlun:
/usr/lib/objrepos:NetApp.SAN_toolkit.scripts:5.0.0.0::COMMITTED:I:Network Appliance SAN Toolkit Scripts:
/usr/lib/objrepos:NetApp.mpio_attach_kit.config:5.0.0.0::COMMITTED:I:Network Applia ce MPIO PCM Kit Path Config Tool:
/usr/lib/objrepos:NetApp.mpio_attach_kit.fcp:5.0.0.0::COMMITTED:I:Network Appliance MPIO PCM Kit FCP Disk ODM Stanzas:
/usr/lib/objrepos:NetApp.mpio_attach_kit.iscsi:5.0.0.0::COMMITTED:I:Network Applian e MPIO PCM Kit iSCSI Disk ODM Stanzas:
/usr/lib/objrepos:NetApp.mpio_attach_kit.pcmodm:5.0.0.0::COMMITTED:I:Network Applia ce MPIO PCM Kit PCM Friend ODM Stanzas:
/usr/lib/objrepos:NetApp.snapdrive:4.1.0.0::COMMITTED:I:Network Appliance SnapDrive
@FAS3140C offlined LUN for hdisk7:

root@x:/oracle/TPM/sapdata1# lspath -F"name parent path_id connection status"|grep ^hdisk7
hdisk7 fscsi0 0 500a0982995ad101,6000000000000 Failed
hdisk7 fscsi0 1 500a0981895ad101,6000000000000 Failed
hdisk7 fscsi1 2 500a0982895ad101,6000000000000 Failed
hdisk7 fscsi1 3 500a0981995ad101,6000000000000 Enabled
root@x:/oracle/TPM/sapdata1#

root@x:~# sanlun lun show|grep hdisk7
root@x:~#

Onlined LUN for hdisk7:

root@x:/oracle/TPM/sapdata1# lspath -F"name parent path_id connection status"|grep ^hdisk7
hdisk7 fscsi0 0 500a0982995ad101,6000000000000 Enabled
hdisk7 fscsi0 1 500a0981895ad101,6000000000000 Enabled
hdisk7 fscsi1 2 500a0982895ad101,6000000000000 Enabled
hdisk7 fscsi1 3 500a0981995ad101,6000000000000 Enabled
root@x:/oracle/TPM/sapdata1#

root@x:~# sanlun lun show|grep hdisk7
yyy: /vol/y/sapdata2/sapdata02.lun hdisk7 fcs1 FCP 150g (161061273600) GOOD
root@x:~#
Questions:

1) why not all paths are Failed?! (isn't this bug?)

2) if LUN is offline, but device is present (hdisk7 is Available , reported by "lsdev -Cc disk |grep hdisk7"), why sanlun reports nothing at all for that hdisk7? Shouldn't it report FAULT/etc? (is this bug too?)

Thanks.

-Jakub Wartak

Originally posted by: jvk

1. last mpio path doesn't fail
2. did you run some IO to hdisk7 at that time?

Originally posted by: jakub.k.wartak

Hi Janez,

1. Do you know why is that?
http://www.computeranddata.com/doc/vendors/ibm/aix/AIX_LVM_IO_Tuning/SANbootMPIO_SDDandSDDPCM.pdf states that SDDPCM does something similiar: "Last path of device is reserved and is never placed into the Failed state".

2. Yes and no (tested both scenarios, the end result it the same).

Originally posted by: dukessd

The last path never fails, this is just one of those things.

I think it has to do with the recovery algorithm, if all pathes were failed there would be no recovery, where as if the last path is not failed the system will keep trying.

If it cannot make contact on the only remaining path then it will try the others in turn...

If all paths were failed the error recovery would not bother trying to contact the device because it is not longer contactable...

Originally posted by: jakub.k.wartak

Thank you very much! :)