From mboxrd@z Thu Jan 1 00:00:00 1970 From: "berk walker" Subject: Re: Migrating from SINGLE DISK to RAID1 Date: Tue, 01 Feb 2005 17:57:32 -0500 Message-ID: References: <41FFD1F8.3010101@gmx.net> Mime-Version: 1.0 Content-Type: text/plain; format=flowed; delsp=yes; charset=utf-8 Content-Transfer-Encoding: 8bit In-Reply-To: <41FFD1F8.3010101@gmx.net> Sender: linux-raid-owner@vger.kernel.org To: Robert Heinzmann , linux-raid@vger.kernel.org List-Id: linux-raid.ids I seem to remember that one can create a degraded array. Then copy over, and shoot the old disk and add it to the aray. b- On Tue, 01 Feb 2005 20:01:12 +0100, Robert Heinzmann wrote: > Hello, > > can someone verify if the following statements are true ? > > - It's not possible to simply convert a existing partition with a > filesystem on it to a raid1 mirror set. > > This may seem succesfull (filesystem can be mounted and must not be > checked), but it will cause data integrity problems. One of the last > Blocks of the device formaly used for file data will be used for the > raid superblock and so all data on this block will be not accessible > anymore. > > - Using a former disk of a raid1 array as a usual disk (not mounted as > degrated /dev/mdX, but instead mounted as /dev/sdX or /dev/hdX) is > successfull. > > This is because the MD device layer reports the device size as size of > disk - superblock offset during the creation of a filesystem on the MD > device. Thus the used size of the disk, when mounting it as /dev/sdX > /dev/hdX, is some KB smaller than it could be, but no data is lost. > > - Its always possible to use raid1 disks as regular disks (not taking > the md autodiscovery into concern). Using regular disks as raid disks > always requires data migration (new filesystem and copy). > > Thank you very much. I would really appreshiate some somments on this > one. > > Robert Heinzmann > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Using Opera's revolutionary e-mail client: http://www.opera.com/m2/