[CentOS] Re: software raid

Sun Apr 1 18:37:49 UTC 2007
Les Mikesell <lesmikesell at gmail.com>

Jeff Lasman wrote:

>> if the hardware can hotswap then you should be ok if i am reading
>> what les said correctly.
> From time to time (not now) I have a machine on my testbed I can test 
> this on.
> Should I break the software RAID first?  I'd think so.

No, you'd expect a failure to automatically kick the drive out of the 
raid and go on about its business.

> Do I have to remake the RAID automatically?  I'd think so.

Yes, you have to 'mdadm --add ...' to make the replacement sync back up.

> Can I physically damage either drive?
> I'd think not.
> So I'm not sure I understand the problem as long as the (sata) drive is 
> in a hotswap bay.
> Anything I'm missing?

The question is whether the kernel will notice the new drive when you 
add it.  It might be possible to swap in an exact match and get away 
with the setup detected at boot time but that doesn't sound very 
healthy.  Can you hotswap a new SATA drive that wasn't present at boot 
time and have the kernel notice the new drive device and its partitions. 
If the partitions are recognized, mdadm will be able to add them.

   Les Mikesell
     lesmikesell at gmail.com