AIX dynamic tracking

Very interesting - we just did a similar migration and neither our AIX administrators or the EMC technicians involved mentioned this possiblity.

We looked at using persistent FCID settings to avoid having devices change on us, but since we did a SAN switch consolidation (multiple McData directors/switches) down to a pair (1 per fabric) of Cisco directors this became unfeasible and we had to do the drop/add devices. With PowerPath this is a fairly trivial excercise (assuming you don't have 100s of AIX hosts) since you can delete every device on an HBA and within PowerPath with a single command.

Based on a quick check of PowerLink looks like EMC does support this with some caveats to get some minimal versions installed: emc155456 and emc115725.

If you do go this route would be interested in hearing how this works-out for you. Learn something new every day

what does "dynamic tracking" do ?

For a good explanation read the AIX connectivity guide, but the short description from what I read is that it would prevent the AIX host from changing the device path when certain changes such as the domain ID of the switch alter the FCID. Does not protect against say changing the WWN (i.e. host HBA) or the target (DMX) WWN from what I could tell.

If you don't use AIX or HP-UX you might not have even realized that some OSes are senstive to things other than the source or target WWNs changing the device path and causing some possible reconfiguration work.

i learn about FCID and cXtXdX relationship on HPUX the hard way . We had an old Brocade 2400 that rebooted itself and lost it's brains ...assigned all targets and initiators new FCIDs, i know it's not an issue if initiators gets new FCID (moving to another port on the switch but getting new FCIDs on the targets killed us. We had to do a lot of exports/imports on HPUX side to fix it.

Dynamic tracking may be recommended depending upon how the migration will be done and how the SAN will be configured. I personally haven't heard anything bad about using it but my speciality is the SAN switches and not this particular Host OS.

I would recommend contacting your local EMC Support Representative to assist you in the migration plan which include the decision on to use Dynamic Tracking or not. You may also want to post again in another EMC Board area that may have more people with AIX specific expertise.

Thank you.

Just an update. IBM highly recommended using this method to migrate to new switch (EMC supports it). It turns out when we change the hba setting to allow dynamic tracking we would get lots of errors (CONFIGURATION_MISMACH). After lots of investigation we found out that our backup software (Commvault) was causing the error. Since we have many hba's that have disk and tape traffic (I know not recommended) we have decided not to use this feature and just use the powerpath remove and re-create method.