ESX drive rebuilds

Lets see who can confirm this am I correct is saying if you have a dell server and it has hardware RAID 5 and one drive fails you can replace the drive make it a hotspare, in the raid manager of course and reboot to finish the rebuild.  The rebuild will happen in the background corrct while VMware is running?

What min precent do I have to be at to reboot and allow to finish in the background?

I dont want to wait for it in the raid manager as i take far too long.

Who is Participating?
Andrew Hancock (VMware vExpert / EE MVE^2)Connect With a Mentor VMware and Virtualization ConsultantCommented:
If you have a RAID array, of type RAID 5, and a disk fails, you will need to replace the disk.

Adding a Hot Spare to the current RAID set, depends on the software on the storage controller, but the existing RAID 5 set would need to be altered to add the FOURTH Hot Spare Disk.

RAID rebuilds will re-build in the background, whilst VMs are running on the datastore, but at reduced performance, Array Rebuild Priority can be specified in some RAID BIOSes as Low, Medium or High.

Depending upon disk types, a RAID 5 rebuild could take several hours!
Nick RhodeIT DirectorCommented:
It will rebuild when you swap it.  Some are much faster than others.  If you fire it up while its rebuilding you will have a performance impact and will see warning signs in the hardward status section in VMware.  You have dell servers and have you looked at installing OMSA on the server running esx or esxi.  This way you can use the remote management tools and check the status of the server through a web gui.


Refer to here for a great guide by Hanccocka:
Actually, depending on the firmware and exact model of controller, a rebuild will not happen unless you swap the HDD hot (meaning while system is running using the same bay).  Rebooting isn't necessary or even advised in any of the Dell controllers.   Also the replacement drive must not have been part of a RAID subsystem so it has no metadata on it.
You cannot make replaced drive (which is already member of raid) hotspare unless you reconfigure raid or have existing hotspare moved to raid,  as for replacing failed drive on Raid-5, you can just hot swap the drive, no need to reboot.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.