From mboxrd@z Thu Jan 1 00:00:00 1970 From: DrYak Subject: raid-0 to raid-5 ? Date: Tue, 31 Jul 2007 14:09:52 +0200 Message-ID: <46AF2690.3000802@bigfoot.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, I have questions regarding the possibilities to migrate a striped array into one with parity check. I currently have a file server with two 300GB IDE drives. They are configured using linux' software RAID in mode 0 (stripped). The raided data is the subsequently partitioned using LVM with a couple of partitions in ReiserFS and JFS format. I have recently acquired a 320GB SATA drive and a compatible SATA controller. I would like to add a 300GB partition from that drive to the stripe to add parity checks for security, transforming the raid set into a raid-5. The machine is running Debian 3.1, but I plan to upgrade to Debian 4.0 somewhere during all the upgrades. Two questions : I. *RAIDRECONF* - Could raidreconf handle correctly the additional 300GB and raid transformation ? I've read on this list that raidreconf has mixed result. Some people report flawless additions to RAIDs, other people report data b0rked beyond any hope of recovery. Has anyone tested a RAID-0 to RAID-5 transformation ? Is it more reliable than RAID-5 addition ? Or is it even less maintained and tested than the raid-5 additions ? (Also, I've read that there are some people wanting to add journalling feature to raidreconf, for better handling of interruptions etc. Is this still developped or was it droped). II. *MDADM --GROW* - The current total of critical data happen to fit within 300GB. What do you think if I : - copy all the critical data to the newer 320GB drive. - create a new RAID-5 set with the original 300GB drives (the set will have somewhere around 300GB free, I think) - LVM partition of the raid set - copy the data back from the 320GB drive - make a 300GB on the new drive, and add it to the RAID as a third drive in the set using the new --GROW option of MDADM Is it possible ? Will LVM correctly survive being on a device that suddenly increases in size ? Thank you a lot and have a nice day. - DrYak -