[CentOS] Re: software raid

Sat Mar 31 19:44:53 UTC 2007
Les Mikesell <lesmikesell at gmail.com>

Cen Tos wrote:
> On 3/31/07, Scott Silva <ssilva at sgvwater.com> wrote:
>> It is the breaking of electrical connections that it trips on. Even if a
>> drive
>> fails, it is still commected, and the system can ignore it. AFAIR you
>> can't
>> hot swap a regular SCSI drive either.
> Does this mean I cannot hotswap a SATA drive in a software RAID array even
> if I have it in a hotswap bay with a SATA hotswap backplane?

Software raid has mdadm commands to fail/remove/add partitions, so it is 
up to the hardware to be able recognize the new working drive.  There 
are scsi-specific commands to remove and re-detect drives and 
firewire/usb normally do it automatically (but not always the way you 
expect).  I'm not sure how SATA fits into this picture.  If the service 
is so critical that you can't run on the single mirror until a 
convenient time to swap with a reboot you might want a hot spare so you 
don't have worry about getting a new drive recognized with the machine 
running.  Even if you didn't dedicate it to an array, if the spare drive 
is in the machine you can easily partition it to match and add it with a 
few commands.

   Les Mikesell
    lesmikesell at gmail.com