Reshape RAID5 to a RAID6 with more (smaller) devices

Reshape RAID5 to a RAID6 with more (smaller) devices

[Roman Mamedov]

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Hello!

I am considering to move my configuration in which I currently use two RAID5
arrays (3*2TB and 3*1TB) to one described in [1]. Specifically, make a 6*1TB
RAID6 plus 3*1TB RAID5 consisting of 2TB drives' "tails".

My question is: does mdadm support a simultaneous reshape, changing at once:
1) RAID5 to RAID6
2) number of devices from 3 to 6
3) individual device size from 2TB to 1TB

Note that the user-accessible space after this reshape does not change, and
remains at 4 TB. So is that supported? Will that require a backup file? Will
that proceed particularly inefficiently/slowly?

[1] http://www.linuxconfig.org/prouhd-raid-for-the-end-user

-- 
With respect,
Roman

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Re: Reshape RAID5 to a RAID6 with more (smaller) devices

[NeilBrown]

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On Wed, 12 Jan 2011 12:29:30 +0500 Roman Mamedov <rm@romanrm.ru> wrote:

> Hello!
> 
> I am considering to move my configuration in which I currently use two RAID5
> arrays (3*2TB and 3*1TB) to one described in [1]. Specifically, make a 6*1TB
> RAID6 plus 3*1TB RAID5 consisting of 2TB drives' "tails".
> 
> My question is: does mdadm support a simultaneous reshape, changing at once:
> 1) RAID5 to RAID6
> 2) number of devices from 3 to 6
> 3) individual device size from 2TB to 1TB
> 
> Note that the user-accessible space after this reshape does not change, and
> remains at 4 TB. So is that supported? Will that require a backup file? Will
> that proceed particularly inefficiently/slowly?
> 
> [1] http://www.linuxconfig.org/prouhd-raid-for-the-end-user
> 

Sorry,  but no.
It could be implemented, probably without a lot of difficulty, but it hasn't
been.

NeilBrown

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