Re: playing with software RAID

[Anand Buddhdev <arb anand org>]

On Tue, Sep 18, 2001 at 06:07:24PM +0200, Leonard den Ottolander wrote:

Hi Leo,

Thanks for the pointers. I've just downloaded the Howto's, and I see a
section in there for simulating failures. So I think I'll give it a try.
Unfortunately, today I had to put the box into production too, so I don't
have much chance to be very dangerous.

> 		Hi Anand,
> 
> > Can someone suggest things I can do to familiarise myself with possible
> > scenarios? I was thinking of shutting down the box, and taking one disk
> > out, to see how the system behaves when restarted (to simulate a failed
> > disk). Is this a good test? And if a disk really does fail, how do I
> > tell? And if I then insert a brand new disk in place of a failed one,
> > how do I set it up to be a part of the RAID configuration? Will the RAID
> > system automatically detect a new disk and rebuild the data on it?
> 
>  I am pretty new to software RAID too, but maybe I can give you some pointers. 
> Of course you should read the Software-RAID-HOWTO and the Root-RAID-HOWTO. 
> There is also a Boot+Root+Raid+LILO mini-howto.
>  Disk failure is reported by the kernel to the console and to 
> /var/log/messages. Taking out a disk is somewhat of a test. When inserting a 
> new disk the RAID device should be rebuilt automatically (I assume the new 
> disk should already be partitioned). The only issue might be the order of the 
> disks in the raidtab. You might have to change the order of the disks to have 
> the RAID device properly rebuilt.
>  You can add extra disks as spares, but you cannot automatically convert a 
> RAID 1 into a RAID 5 when you add an extra disk.

-- 
Anand Buddhdev