Re: Confusion with setting up new RAID6 with mdadm

[Zoltan Szecsei <zoltans@geograph.co.za>]

On 2010-11-15 00:13, Neil Brown wrote:
>
> Depending on which version of mdadm you are using, the default chunk size
> will be 64K or 512K.  I would recommend using 512K even if you have an older
> mdadm.  64K appears to be too small for modern hardware, particularly if you
> are storing large files.
>    
root@gs0:/home/geograph# mdadm -V
mdadm - v2.6.7.1 - 15th October 2008
root@gs0:/home/geograph#

This was what apt-get install got for me, from Ubuntu 10.04 64bit Desktop.
Should I download & compile a newer one?
(Where from? - haven't found the mdadm developer page yet))


> For raid6 with the current implementation it is safe to use "--assume-clean"
>    
Is my above version "current" enough?
> to avoid the long recovery time.  It is certainly safe to use that if you
> want to build a test array, do some performance measurement, and then scrap
> it and try again.  If some time later you want to be sure that the array is
> entirely in sync you can
>    echo repair>  /sys/block/md0/md/sync_action
> and wait a while.
>
> I agree with what Mikael and Luca suggested - particularly the suggested for
> "--bitmap internal".  You really want that.
>
>
> N
>    

Regards & thanks,
Zoltan


-- 

===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
P.O. Box 7, Muizenberg 7950, South Africa.

65 Main Road, Muizenberg 7945
Western Cape, South Africa.

34° 6'16.35"S 18°28'5.62"E

Tel: +27-21-7884897  Mobile: +27-83-6004028
Fax: +27-86-6115323     www.geograph.co.za
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