Re: RAID 1: Can't mirror drives
RH 7.2 OK, is there a better source of instructions on creating RAID 1 configs on existing drives for Red Hat distributions? I checked the Red Hat Docs and can only find instructions for setting up RAID upon new installation, not on an existing system. The FAQ that I referred to: http://unthought.net/Software-RAID.HOWTO/ doesn't mention that you can't mirror a mounted partition or address the issue of how to set up mirrors w/ production drives that have existing data. The FAQ does have a separate section on setting up RAID on Red Hat systems, but only addresses changes needed booting w/ LILO, but not the current default boot manager GRUB. I'd like to get as much relevant info as possible to avoid blowing my system away and being very sorry... Thanks, Cosmo ps: I'm surprised to be informed that one can't mirror a mounted drive. Doesn't a recovery from a failed RAID drive involve replacing a bad drive with a good one, and then re-mirroring the new one from an existing on-line copy - w/o taking the original off-line? Hi Cosmo, /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. You can't make a raid device using a mounted device. Unmount it and build the array from a rescue system. Not sure if that will preserve the data on /dev/sda2 though. Bye, Leonard. I can't get my RAID 1 mirrors set up. Following instructions from the Software RAID HowTo at http://unthought.net/Software-RAID.HOWTO/ I've run `mkraid /dev/md0` but get the following errors. However, there are no errors in the message syslog file, nor any indication from /proc/mdstat. What's up wit that? My /etc/raidtab: # root partition mirrors raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 persistent-superblock 1 device /dev/sda2 raid-disk 0 device /dev/hdc2 raid-disk 1 Both /dev/sda2 and /dev/hdc2 have partition types of fd (linux-raid). /dev/sda2 is my root partition, currently mounted. `fdisk` reports /dev/sda2 as having 3,855,600 blocks `fdisk` reports /dev/hdc2 as having 3,856,104 blocks Output from `mkraid`: # /sbin/mkraid /dev/md0 handling MD device /dev/md0 analyzing super-block disk 0: /dev/sda2, 3855600kB, raid superblock at 3855488kB /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. # cat /proc/mdstat Personalities : read_ahead not set unused devices: none # Help, please. Thanks. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
Re: RAID 1: Can't mirror drives
If you have a system disk, and want to add a spare disk and make the two together a RAID-1 drive, do the following: * Add your disk (let's say it's hdb). * Set up your raid config with your current system disk as a fiailed disk (let's say it's hda). * Start up your RAID volume and mount it somewhere * Copy your system disk to your RAID volume. * Modify /etc/fstab of your RAID system, GRUB, and/or LILO to boot off of your RAID volume. You may need to mkinitrd as well. * Make a grub boot disk just to be safe, and read the grub manual so that you know how to use it. * Reboot your system. The raid device should be your root device. Check that everything works. If so, add your original system disk back to the array, and let it resync. Jon On Mon, 28 Jul 2003, Cosmo Lee wrote: RH 7.2 OK, is there a better source of instructions on creating RAID 1 configs on existing drives for Red Hat distributions? I checked the Red Hat Docs and can only find instructions for setting up RAID upon new installation, not on an existing system. The FAQ that I referred to: http://unthought.net/Software-RAID.HOWTO/ doesn't mention that you can't mirror a mounted partition or address the issue of how to set up mirrors w/ production drives that have existing data. The FAQ does have a separate section on setting up RAID on Red Hat systems, but only addresses changes needed booting w/ LILO, but not the current default boot manager GRUB. I'd like to get as much relevant info as possible to avoid blowing my system away and being very sorry... Thanks, Cosmo ps: I'm surprised to be informed that one can't mirror a mounted drive. Doesn't a recovery from a failed RAID drive involve replacing a bad drive with a good one, and then re-mirroring the new one from an existing on-line copy - w/o taking the original off-line? Hi Cosmo, /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. You can't make a raid device using a mounted device. Unmount it and build the array from a rescue system. Not sure if that will preserve the data on /dev/sda2 though. Bye, Leonard. I can't get my RAID 1 mirrors set up. Following instructions from the Software RAID HowTo at http://unthought.net/Software-RAID.HOWTO/ I've run `mkraid /dev/md0` but get the following errors. However, there are no errors in the message syslog file, nor any indication from /proc/mdstat. What's up wit that? My /etc/raidtab: # root partition mirrors raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 persistent-superblock 1 device /dev/sda2 raid-disk 0 device /dev/hdc2 raid-disk 1 Both /dev/sda2 and /dev/hdc2 have partition types of fd (linux-raid). /dev/sda2 is my root partition, currently mounted. `fdisk` reports /dev/sda2 as having 3,855,600 blocks `fdisk` reports /dev/hdc2 as having 3,856,104 blocks Output from `mkraid`: # /sbin/mkraid /dev/md0 handling MD device /dev/md0 analyzing super-block disk 0: /dev/sda2, 3855600kB, raid superblock at 3855488kB /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. # cat /proc/mdstat Personalities : read_ahead not set unused devices: none # Help, please. Thanks. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
Re: RAID 1: Can't mirror drives
Hi Cosmo, doesn't mention that you can't mirror a mounted partition or address the issue of how to set up mirrors w/ production drives that have existing data. Setting up RAID arrays on a running system works the same as before installation, but you have to use free partitions. If you want to add a partition with data to an array you will have to move the data before proceeding to create the array. I'd like to get as much relevant info as possible to avoid blowing my system away and being very sorry... Have a look at http://www.tldp.org for docs. ps: I'm surprised to be informed that one can't mirror a mounted drive. Doesn't a recovery from a failed RAID drive involve replacing a bad drive with a good one, and then re-mirroring the new one from an existing on-line copy - w/o taking the original off-line? The point is that you did not setup the array yet. hda2 is mounted as hda2, not as part of the array md0. So you need to unmount it, create the array and then remount the array. Bye, Leonard. -- How clean is a war when you shoot around nukelar waste? Stop the use of depleted uranium ammo! End all weapons of mass destruction. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
Re: RAID 1: Can't mirror drives
Hi Cosmo, From http://unthought.net/Software-RAID.HOWTO/Software-RAID.HOWTO- 4.html#ss4.12 : 4.12 Root filesystem on RAID In order to have a system booting on RAID, the root filesystem (/) must be mounted on a RAID device. Two methods for achieving this is supplied bellow. The methods below assume that you install on a normal partition, and then - when the installation is complete - move the contents of your non-RAID root filesystem onto a new RAID device. Bye, Leonard. -- How clean is a war when you shoot around nukelar waste? Stop the use of depleted uranium ammo! End all weapons of mass destruction. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
RAID 1: Can't mirror drives
RH 7.2 I can't get my RAID 1 mirrors set up. Following instructions from the Software RAID HowTo at http://unthought.net/Software-RAID.HOWTO/ I've run `mkraid /dev/md0` but get the following errors. However, there are no errors in the message syslog file, nor any indication from /proc/mdstat. What's up wit that? My /etc/raidtab: # root partition mirrors raiddev /dev/md0 raid-level 1 nr-raid-disks 2 nr-spare-disks 0 chunk-size 4 persistent-superblock 1 device /dev/sda2 raid-disk 0 device /dev/hdc2 raid-disk 1 Both /dev/sda2 and /dev/hdc2 have partition types of fd (linux-raid). /dev/sda2 is my root partition, currently mounted. `fdisk` reports /dev/sda2 as having 3,855,600 blocks `fdisk` reports /dev/hdc2 as having 3,856,104 blocks Output from `mkraid`: # /sbin/mkraid /dev/md0 handling MD device /dev/md0 analyzing super-block disk 0: /dev/sda2, 3855600kB, raid superblock at 3855488kB /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. # cat /proc/mdstat Personalities : read_ahead not set unused devices: none # Help, please. Thanks. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
Re: RAID 1: Can't mirror drives
Hi Cosmo, /dev/sda2 is mounted mkraid: aborted, see the syslog and /proc/mdstat for potential clues. You can't make a raid device using a mounted device. Unmount it and build the array from a rescue system. Not sure if that will preserve the data on /dev/sda2 though. Bye, Leonard. -- How clean is a war when you shoot around nukelar waste? Stop the use of depleted uranium ammo! End all weapons of mass destruction. -- redhat-list mailing list unsubscribe mailto:[EMAIL PROTECTED] https://www.redhat.com/mailman/listinfo/redhat-list
