So I have recently joined a company with a 7 device group with 3 pools - T1, T2 and T3, all running 8.1.6 firmware.

One of the devices is a PS6000xv with Type7 controllers - the firmware notes have the following to say: "Members with Type 7 or Type 10 controllers in the group show high latency during firmware updates, which can lead to I/O failures" - unfortunately this device is in the T1 pool.

I have enough space in the pool to move this device to the maintenance pool whilst firmware updates are being done.

MEM and HIT are (or will be) installed on all devices that access iSCSI directly.  I will have to check the disk timeout settings on the VM's.

So the question is do I go for the Dell Storage Update Manager path of updating, or shuffle devices in and out of the maintenance pool for updates and manually update, or a mix of both (move the one potentially troublesome to maintenance then use DSUM)?

FYI DSUM will take 3 hours per firmware level to update, so will probably be done out of core hours, say 1am.