Switch running System to RAID-1
in [Debian]
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From: alexandrus on 21 Dec 2007 18:20 Hi, I just figured that our complany's server was running on JBOD with 2 HDs, one of them entirely unused (d'oh!). Of course I would like to have it as RAID 1. Now, I built an Array from the HD in use and know how to make it bootable, but I suppose I have to make some changes to the boot-config before it will run as before. Which could these be? Also (probably a common question) how can I make a backup boot CD-ROM with the current settings? Is there a good HowTo around? Alex -------- system info: hwinfo says the Controller is "Intel 6300ESB SATA RAID Controller". boot-loader should be GRUB. Kernel 2.6.8-2-386. PS: Needless to say, I have a complete backup. PPS: Posted this the second time here because I was told it was OT in Linux Boot list, where I posted initally. -- View this message in context: http://www.nabble.com/Switch-running-System-to-RAID-1-tp14464060p14464060.html Sent from the Debian User mailing list archive at Nabble.com. -- To UNSUBSCRIBE, email to debian-user-REQUEST(a)lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmaster(a)lists.debian.org
From: Douglas A. Tutty on 21 Dec 2007 20:20 On Fri, Dec 21, 2007 at 03:12:22PM -0800, alexandrus wrote: > I just figured that our complany's server was running on JBOD with 2 HDs, > one of them entirely unused (d'oh!). Of course I would like to have it as > RAID 1. > > Now, I built an Array from the HD in use and know how to make it bootable, > but I suppose I have to make some changes to the boot-config before it will > run as before. Which could these be? > > Also (probably a common question) how can I make a backup boot CD-ROM with > the current settings? Is there a good HowTo around? > system info: > hwinfo says the Controller is "Intel 6300ESB SATA RAID Controller". > boot-loader should be GRUB. > Kernel 2.6.8-2-386. > > PS: Needless to say, I have a complete backup. > PPS: Posted this the second time here because I was told it was OT in Linux > Boot list, where I posted initally. We saw a very long thread not that long ago on why going from JOBD to raid is either extremely difficult or impossible. Having two drives on one controller and then using software raid doesn't mean that one disk failing won't take out the controller and possibly the second disk. Be careful in your expectations. If that were a true hardware raid controller, you would only tell Debian to forget the second drive and tell the controller to add the second drive to the array. The best backup boot CD is the Debian installer's rescue mode which will assemble the raid array (and any LVM over top of it) and give you a chroot shell. Also, your kernel is well out-of-date so you should be updating that server to the most recent Etch. Another kernel update today; current version is 2.6.18-5. Also, unless the server is running a 486, there is probably a more appropriate kernel within the i386 flavour. --- Since the second drive is unused right now, to change to raid1, I'd suggest a fresh install onto that second drive setting up raid1 with just the one drive (a degraded array), with LVM overtop. Transfer the data over, change the grub menu.list so it defaults to the new install, then add the old disk into the raid1 array. YMMV. Doug. -- To UNSUBSCRIBE, email to debian-user-REQUEST(a)lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmaster(a)lists.debian.org
From: Scott Gifford on 22 Dec 2007 01:10 alexandrus <deralex84-forum(a)yahoo.de> writes: > Hi, > I just figured that our complany's server was running on JBOD with 2 HDs, > one of them entirely unused (d'oh!). Of course I would like to have it as > RAID 1. > > Now, I built an Array from the HD in use and know how to make it bootable, > but I suppose I have to make some changes to the boot-config before it will > run as before. Which could these be? If you're using software RAID, the boot device will now be "/dev/md?". You will need to configure your boot loader (grub or LILO) to boot from that partition, make sure your initrd loads all of the right modules, and change your /etc/fstab to mount the md devices instead of the hard drive devices. I have found this to be surprisingly tricky to get right on the first try, so make sure you have a boot disk handy. Creating a configuration file for the RAID devices seemed to help mkinitrd/yaird figure out that it needed the RAID modules. grub seemed to have better support for RAID than lilo, although it was a bit "magical" and hard to debug when it didn't work properly. At one point I found some useful instructions with google, but I can't seem to find them now. Still, there seem to be some useful howto guides that should get you pointed in the right direction. Good luck! ----Scott. -- To UNSUBSCRIBE, email to debian-user-REQUEST(a)lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmaster(a)lists.debian.org
From: Douglas A. Tutty on 22 Dec 2007 09:20 On Sat, Dec 22, 2007 at 01:05:31AM -0500, Scott Gifford wrote: > alexandrus <deralex84-forum(a)yahoo.de> writes: > > > Hi, > > I just figured that our complany's server was running on JBOD with 2 HDs, > > one of them entirely unused (d'oh!). Of course I would like to have it as > > RAID 1. > > > > Now, I built an Array from the HD in use and know how to make it bootable, > > but I suppose I have to make some changes to the boot-config before it will > > run as before. Which could these be? > > If you're using software RAID, the boot device will now be "/dev/md?". > You will need to configure your boot loader (grub or LILO) to boot > from that partition, make sure your initrd loads all of the right > modules, and change your /etc/fstab to mount the md devices instead of > the hard drive devices. For Etch's install, grub can't boot from a raid array as /dev/md?. It can read a single disk, so if its a raid1 array, both (all) partitions are the same. My /boot is on raid1 and my Grub menu.list has entries for /dev/sda1 and /dev/sda2. I have installed grub onto the MBR of both disks so that I can still use a menu item to boot if one drive is missing. > > I have found this to be surprisingly tricky to get right on the first > try, so make sure you have a boot disk handy. > > Creating a configuration file for the RAID devices seemed to help > mkinitrd/yaird figure out that it needed the RAID modules. grub > seemed to have better support for RAID than lilo, although it was a > bit "magical" and hard to debug when it didn't work properly. > > At one point I found some useful instructions with google, but I can't > seem to find them now. Still, there seem to be some useful howto > guides that should get you pointed in the right direction. Once GRUB boots, its easiest to use filesystem lables for device names for the kernel and in fstab. Then the kernel can hunt and find what it needs. LVM over top of raid also works a treat. Doug. -- To UNSUBSCRIBE, email to debian-user-REQUEST(a)lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmaster(a)lists.debian.org
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