From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Szecsei Subject: Re: Confusion with setting up new RAID6 with mdadm Date: Mon, 15 Nov 2010 08:58:12 +0200 Message-ID: <4CE0DA04.1010308@geograph.co.za> References: <4CE00206.4000301@geograph.co.za> <20101115091326.42b38b84@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20101115091326.42b38b84@notabene.brown> Sender: linux-raid-owner@vger.kernel.org Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids 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 a= n older > mdadm. 64K appears to be too small for modern hardware, particularly= if you > are storing large files. > =20 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 Deskt= op. 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" > =20 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 ar= ray 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 sugges= ted for > "--bitmap internal". You really want that. > > > N > =20 Regards & thanks, Zoltan --=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 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=B0 6'16.35"S 18=B028'5.62"E Tel: +27-21-7884897 Mobile: +27-83-6004028 =46ax: +27-86-6115323 www.geograph.co.za =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1153 / Virus Database: 424/3256 - Release Date: 11/14/10 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html