DM-multipath Instrumentation
We're about to undergo a global code-upgrade across all of the storage processors on one of our vendors SANs. So, I was wanting to write a script to run against all of our RHEL systems to see:
- Which hosts were mounting storage from the target SAN arrays (easily done)
- Which the preceding hosts were referencing their LUNs via DM-multipath (easily done)
- Whether the preceding hosts multipathds were set up according to standards - or at least in a way that will be resilient to the storage processors being sequentially rebooted as part of their firmware upgrade process (doable, but really a kludge from what I can tell)
From where I'm sitting, hacking at my scripts, it seems like DM-multipath lacks a lot in the way of instrumentations. While I can dump out the entire DM-multipath configuration (via `echo "show config" | multipathd -k`) and then parse the output, that's rather ugly and error-prone. I've Googled around, quite a bit, and have yet to strike upon the magic incantation that allows me to pull JUST specific parameters from DM-multipath (e.g., polling_interval, failback, hardware_handler, etc.). Does anyone know of a way to pull just the targeted parameters - perferably at the per-VENDOR or even per-device level?
