[CentOS] Re: software raid

Sun Apr 1 12:15:43 UTC 2007
William Warren <hescominsoon at emmanuelcomputerconsulting.com>

if the hardware can hotswap then you should be ok if i am reading what 
les said correctly.

Les Mikesell wrote:
> 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.
> 

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