[opensuse] Re: software RAID vs BIOS RAID
James Knott wrote:
Per Jessen wrote:
John Andersen wrote:
At one time there was a problem having /boot on raid, and its been a while since I had to reconfigure a fresh box, so I don't know if this is still the case.
With lilo it works fine, but I don't know about grub.
It doesn't work with grub. With RAID and also LVM, /boot has to be on a regular partition.
Here LVM is the problem, not RAID-1. With RAID-1 via md and no LVM, /boot on a mirrored ext3/ext4 filesystem definitively works with grub. We use it since several years, and had enough disk errors to prove it working. One needs to take care that grub bootloader is installed on both disks, though, openSUSE doesn't do this itself during installation. Extra robustness comes with stanzas that name both disks, in case hd0 is not visible to the BIOS any more and hd1 suddenly gets hd0. Joachim -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Joachim Schrod Email: jschrod@acm.org Roedermark, Germany -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Joachim Schrod wrote:
James Knott wrote:
Per Jessen wrote:
John Andersen wrote:
At one time there was a problem having /boot on raid, and its been a while since I had to reconfigure a fresh box, so I don't know if this is still the case.
With lilo it works fine, but I don't know about grub.
It doesn't work with grub. With RAID and also LVM, /boot has to be on a regular partition.
Here LVM is the problem, not RAID-1.
With RAID-1 via md and no LVM, /boot on a mirrored ext3/ext4 filesystem definitively works with grub. We use it since several years, and had enough disk errors to prove it working. One needs to take care that grub bootloader is installed on both disks, though, openSUSE doesn't do this itself during installation. Extra robustness comes with stanzas that name both disks, in case hd0 is not visible to the BIOS any more and hd1 suddenly gets hd0.
Joachim
I was wondering about that. Also, the boot menu points to a specific kernal. How does that get updated with RAID 1? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Joachim Schrod wrote:
Here LVM is the problem, not RAID-1.
With RAID-1 via md and no LVM, /boot on a mirrored ext3/ext4 filesystem definitively works with grub. We use it since several years, and had enough disk errors to prove it working. One needs to take care that grub bootloader is installed on both disks, though, openSUSE doesn't do this itself during installation. Extra robustness comes with stanzas that name both disks, in case hd0 is not visible to the BIOS any more and hd1 suddenly gets hd0.
Perhaps someone should do a HOWTO on this. I recently set up a server at work with RAID 4 for most of the system, but /boot is not on RAID. If I'd known about this I would have done it. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On 9/18/2011 5:17 AM, James Knott wrote:
Joachim Schrod wrote:
Here LVM is the problem, not RAID-1.
With RAID-1 via md and no LVM, /boot on a mirrored ext3/ext4 filesystem definitively works with grub. We use it since several years, and had enough disk errors to prove it working. One needs to take care that grub bootloader is installed on both disks, though, openSUSE doesn't do this itself during installation. Extra robustness comes with stanzas that name both disks, in case hd0 is not visible to the BIOS any more and hd1 suddenly gets hd0.
Perhaps someone should do a HOWTO on this. I recently set up a server at work with RAID 4 for most of the system, but /boot is not on RAID. If I'd known about this I would have done it.
Why Raid 4? Its pretty rare for that to be used anymore. -- _____________________________________ ---This space for rent--- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On 9/18/2011 8:17 AM, James Knott wrote:
Joachim Schrod wrote:
Here LVM is the problem, not RAID-1.
With RAID-1 via md and no LVM, /boot on a mirrored ext3/ext4 filesystem definitively works with grub. We use it since several years, and had enough disk errors to prove it working. One needs to take care that grub bootloader is installed on both disks, though, openSUSE doesn't do this itself during installation. Extra robustness comes with stanzas that name both disks, in case hd0 is not visible to the BIOS any more and hd1 suddenly gets hd0.
Perhaps someone should do a HOWTO on this. I recently set up a server at work with RAID 4 for most of the system, but /boot is not on RAID. If I'd known about this I would have done it.
The problem is there are several steps that are essentially unsupportable by suse until they build the support into yast and other system scripts and tools. I guess it would be cool anyways but it would be a longish document because you'd have to explain everything that the system doesn't do automatically. Then again such howtos have existed for other distros for years http://www.texsoft.it/index.php?c=hardware&m=hw.storage.grubraid1&l=it In fact it's been doable for so long that many of the existing howto's refer to lilo instead of grub or refer to building your kernel to get the support. We don't need any of that. We WOULD need to document: * How to manually assemble the main non-bootable array if the initrd failed to do it, which does happen sometimes. * How to ensure initrd gets regenerated with the required raid modules included, because by default it may or may not. (edit /etc/sysconfig/kernel and then run mkinitrd, and maybe do all this after manually booting into the install media, manually assembling the array, mounting the filesystem, bind mounting /dev/ /proc /sys into the mounted fs, and finally chrooting into the installed but not yet bootable system...) -- bkw -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
participants (4)
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Brian K. White -
James Knott -
Joachim Schrod -
John Andersen