mfi (Dell H700) + hot swapping doesn't appear to work with RC1

[Borja Marcos]

On Dec 14, 2011, at 2:09 PM, Hugo Silva wrote:

> Hello,
> 
> First of all apologies if this has been fixed in RC3. I set this server
> up with mfsbsd, which is RC1, and didn't get to update the system yet.
> 
> This box has 6 hdds, a 2-mirror zpool was set up as the root pool, with
> 2 spares.
> 
> While testing hot swapping I noticed that while the controller detects
> disk removal/insertion, the zpool will never recover. The problem seems
> to be deeper than ZFS, as disklabel/fdisk/etc also fail on the
> removed-and-reinserted disk.
> 
> At the ZFS level, doing a zpool clear yields more errors on the removed
> disk; rebooting becomes the only option to make the pool healthy again.
> 
> 
> Is this normal? Did I miss any step?

I assume that you have tried to use the H700 as a "JBOD" card, defining logical volume for each hard disk.

The problem is: that gorgeous, fantastic, masterful, Nobel award candidate card, has a wonderful behavior in that case. If you extract one of the disks, the logical volume associated to it is invalidated. So, you insert a replacement disk, and the card refuses to recognize the volume. What is even worse, in order to recover it's mandatory to reboot the complete system *AND* go through the RAID configuration utility.

That's the problem. The card refuses  to work as a simple disk controller without frills, and the frills get in the way.

To summarize: it isn't FreeBSD's fault, no matter which version you use. It's a "feature" coming directly from the geniuses who designed the card.





Borja.