From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Valiquette Subject: Re: nested raid possible? Date: Fri, 06 Jul 2007 01:49:58 -0400 Message-ID: <468DD806.6070608@ieee.org> References: <8585506.1183693119573.JavaMail.root@wombat.diezmil.com> Reply-To: linux-raid@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-reply-to: <8585506.1183693119573.JavaMail.root@wombat.diezmil.com> Sender: linux-raid-owner@vger.kernel.org To: turbo@weasel.com Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids turbo@weasel.com un jour =C3=A9crivit: > I have a raid-5 array of six 250gb hard drives. > I just bought four 500gb hard drives. >=20 > I know I can take the six drives and make three raid-1 arrays of 500g= b. Here, you probably means three RAID-0 arrays of 500GB, otherwise you= =20 would get three RAID-1 of 250GB. > After doing that, can I make a raid-5 array consisting of the three=20 > raid-0 arrays, and the four 500gb hard drives? Yes, It would works, because all you need is to get a block device.=20 Software Raid takes many block devices to generate one block device, so= It=20 is transparent. That said, I don't say that It is a good idea to do It as you are=20 suggesting. You realize that It would be less reliable than a RAID-5=20 array made of seven 500GB drive. If you really want to do than, I would feel more confident using=20 RAID-6. Another option is to use RAID-10 with 4x250GB with 2 hot spar= e,=20 and connect everything in a RAID-5 array for a total of also 2.5TB of=20 usable space. Personnaly, considering the price of the hard drives, I=20 won't ever bother and use only 500GB drive. That said, It is your data. It is you that know if It is better to=20 have the full 3TB, at the cost of somewhat more risk to loose your data= =2E=20 Maybe the additional risk is low enough for your needs, I don't know. But in a business environment, I would normaly not do It. Simon Valiquette - 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