Re: Is shrinking raid5 possible?

[Paul Davidson <Paul.Davidson@anu.edu.au>]

Neil Brown wrote:
> Yep.
> The '--size' option refers to:
>               Amount  (in  Kibibytes)  of  space  to  use  from  each drive in
>               RAID1/4/5/6.  This must be a multiple of  the  chunk  size,  and
>               must  leave about 128Kb of space at the end of the drive for the
>               RAID superblock.  
> (from the man page).
> 
> So you were telling md to use the first 600GB of each device in the
> array, and it told you there wasn't that much room.
> If your array has N drives, you need to divide the target array size
> by N-1 to find the target device size.
> So if you have a 5 drive array, then you want
>   --size=157286400
> 
> NeilBrown

Thanks, and sorry for not being able to read properly -- I read this at
least three times and didn't notice it was the drive size and not the
array size.

Cheers, Paul.