Hot-Swapping hard drives on Dell PowerEdge 2850 running FBSD 5.5-PRE

Alex Zbyslaw xfb52 at
Fri Jun 23 09:03:09 UTC 2006

Alex Franks wrote:

> Hello all,
> I'm getting ready to install 2 identical drives into the available
> drive bays in my 2850. However, it would be highly preferable that
> this machine NOT be shut down in order to install these drives. I know
> from looking at the docs that these drive bays are hot-swappable, but
> I'd like to know before I attempt this that someone else out there has
> successfully performed a hot-swap or hot-install of drives on a 2850
> or comparable Dell PowerEdge running FreeBSD.

RAID-1 I assume and PERC 4e/Di.  Yes, did it when testing fresh 
machines.  The controller BIOS has a setting for how much resource to 
allocate to the recovery of the inserted drive (0?-100%); the lower you 
set it the slower it will recover the disk, but the higher you set it 
the slower the machine will go. I think we went for 70% as the machine 
never gets *that* heavy disk usage.

If the machine isn't live yet, then just do a basic install from CD (<30 
mins) and then try the hotswap test.  That way you can't lose any data 
even if something goes wrong.

My advice with these machines is never to swap any disk with the machine 
off - the controller gets confused.  Stick with hotswapping and it seems 
fine.  I think you can set up an auto-spare so that if a disk fails the 
array is rebuilt automatically using the spare.

Use sysutils/megarc for monitoring the RAID from BSD.


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