Rescan doesn't show new LUNs on FC HBA...need to reboot?

[Whaler]

On our ESX 4.1.0 boxes, we attached an unused FC HBA from each server to a new SAN and presented LUNS.

The HBA's always did show up in vCenter, but I expected that after doing a "Rescan All" the new LUNs would show up as devices on those HBAs, but they don't.

I'm told that "Rescan" never works for us, and the server needs to be rebooted.  Is that true?  Seems like a reboot shouldn't be necessary.

Thanks....

[Josh26]

A rescan should be all that is needed.

I would suspect patch updates, HCL/driver compatability, or SAN configuration issues.

[rpotru]

I don't think you need to reboot. Rescan should work if LUNs are presented properly. I would check with the storage to make sure LUNs are presented properly.

[weinstein5]

I put a third vote to check the SAN configuration - 

[Whaler]

Well thanks to all of you for such a quick response.  3 out of 3 agree!

I'm told our patch level is totally up to date, so we're assuming something is amiss with the config of the Hitachi SAN or Cisco switches.

I'll probably reboot one server and report back.  Thanks again....

[Whaler]

I'm told by our guys here that when san storage is first connected to the esx hba, a reboot is required.  Subsequently added luns can be probed for without a reboot.

Sound right?  Thanks to all....

[weinstein5]

Not true -  as long as the HBA is supported by VMware and the LUN zoned and presented correctly to the ESXi host all you will need to do is rescan and the LUN should be discovered -

[coafark]

Just to toss my 2 cents in.  I have the same issue with some LUNs on my ESXi 4 and ESXi 5 hosts.

I have a feeling that its on the SAN side also, but we don't control that and their answer is "they are all set up the same way".  When they make changes to existing ones, I see that, just "some" new LUNs don't show up til I reboot the host.

Right clicking on the HBA  and picking rescan, picking Rescan All (from the storage adapters), etc does nothing for those few that don't show up.

Across multiple versions and patch levels of hosts also.

FC HBAs using Hitachi back end.