I'm currently putting together some ideas for a new VMHost using ESXi with RAID 5 to replace 3 aging ESXi hosts that have no RAID. However I can't seem to find any good info explaining how to monitor and rebuild a RAID 5 'online' with ESXi as the host OS. I know ESXi can be installed onto a RAID volume but how can a fault be detected and the raid rebuilt without shutting down the system, replacing the drive, booting into the RAID BIOS and initiating a rebuild. Is there a specific feature in a RAID card I should be looking for? Can this be done with IPMI or something similar?

EDIT: So this is a small home lab, I don't have the full brunt of corporate money behind me to leverage HP Smart Arrays. I was attempting to do this on the cheap. I meant to explain that I was planning hardware RAID 5 through Direct Attached Storage. However it's becoming ever more evident that using network storage is the more preferred option here. My worry again is over running my small budget with newer NAS servers and 10Gbe switches, etc... I am and plan to continue to control the ESXI through vSphere. I realize some RAID systems can be configured to rebuild, but I was hoping to gain more control over the raid and initiate a resyc or a scrub, alert me to failures, etc... I'm currently using ESXi 5.1 but have no problem upgrading to 5.5.

  • Server Hardware is Dell Poweredge? – Nils Mar 18 '15 at 6:28
  • I don't really agree the downvote - I think this is a good question. If you think it is reparable, please explain your problem here and I will be ready to fix that. – peterh Mar 18 '15 at 7:53
  • If you're thinking of doing this with large disks (=>1TB) please don't use R5, use R10 or R6/60 - R5 is now essentially obsolete. – Chopper3 Mar 18 '15 at 8:00
  • This totally depends. What type of server do you have? – ewwhite Mar 19 '15 at 17:47

There is no information about versioning so I would try to be as much useful as possible without entering into too much detail. I assume you have a vSphere system controller the ESXi.

There are CIM providers that are able to monitor specific hardware devices. You can find a list here. In this other link, you can find an example for an specific model (MegaRAID).

Regarding degraded RAID groups (with faulty disks), normally the system starts the rebuild once you replace the disk that belongs it.

Hope this helps.

  • Many raid controllers will not automatically initiate a rebuild without the user telling the raid controller to use the newly installed disk. – steampowered Nov 21 '15 at 6:25

(Your didn't mention, but you wanted hardware raid, so I inserted this into your question.)

From the viewpoint of the "OS" (in this case, the hypervisor), the raid array seems to be a single "hard disk". Anything over this, any extra functionality (for example, quering the status of the volumes or change the raid level) needs extra driver. These exist for esxi or not.

The "normal" solution is to get a raid card device supported by the ESXi. Here you can get a lot of help by the vmware hardware compatibiluity guide. Although this list is maybe too narrow - I've seen multiple rock solid esxi systems which didn't had a single hardware element on this list.

Maybe a trickier solution were to somehow handle the storage a little bit "indirectly":

  1. Either by the directpath functionality (google for that, it is very funny feature). It would mean, that a single vps had access to the physical raid device, and it shared the volumes to your local virtual network (by nfs or by iscsi (my subjetive vote for the second))
  2. Or doing the whole storage out of your system, in a local network storage solution.

On my own experience is that vmware (the company) somehow likes the second.

P.s. You didn't asked explicitly, but maybe it will be useful for you to know: Vmware ESXi supports raw block devices.

  • Yes, I was planning hardware RAID through DAS. I'm now seriously considering NAS and some 10Gbe lanes. – Primordial Mar 19 '15 at 23:08

I don't know about other server vendors but you can Manage an HP Smart Array directly from VMware ESXi. This is about an older ProLiant (G5) and ESXi version (5.0 / 5.1) but should be possible with current ProLiants and ESXi version, too.

In case you have HP servers you can configure HP iLO to send SNMP traps to your monitoring product.

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