[CentOS] Software Raids Questions (I have only ever used hardware?)

Ross Walker rswwalker at gmail.com
Mon Sep 28 13:39:48 UTC 2009


On Sep 27, 2009, at 9:35 PM, Karanbir Singh <mail-lists at karan.org>  
wrote:

> On 28/09/09 02:11, Ross Walker wrote:
>>> Eg. to convert this setup into a raid-5 : start with a 1 disk raid-1
>>> degraded, move a disks worth of data onto there, bring in the second
>>> disk and let them sync into a 'normal' raid1 state, then convert  
>>> that
>>> into a raid-5 with the 3rd disk. then bring in the 4th disk as
>>> hotspare.
>>>
>>> with TiB's worth of data, its not going to be quick.
>>
>> Can you convert a RAID0 to a RAID5?
>
> How would you create a 1 disk degraded raid0 :) well, you could - but
> you wont get any data onto it! So you would need to start with 2  
> disks,
> and with that you then need to store 2 disks worth of stuff somewhere
> while this is building[1].

Can't you start with a single disk raid0 and expand? I think that is  
possible no? Then with a two disk raid0 add a parity disk (raid4) then  
distribute the parity for a raid5.

Of course if Linux RAID doesn't support that then it can't be done  
yet, but it would be possible.

-Ross
  



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