Re: raid1 or raid10 for /boot
Keld Jørn Simonsen wrote: I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? I don't know about you, but my /boot goes with zero use between boots, efficiency and performance improvements strike as a distinction without a difference, while adding complexity without benefit is always a bad idea. I suggest that you avoid having a learning experience and stick with raid1. -- Bill Davidsen [EMAIL PROTECTED] Woe unto the statesman who makes war without a reason that will still be valid when the war is over... Otto von Bismark - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: raid1 or raid10 for /boot
On Wed, Feb 06, 2008 at 01:52:11PM -0500, Bill Davidsen wrote: Keld Jørn Simonsen wrote: I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? I don't know about you, but my /boot goes with zero use between boots, efficiency and performance improvements strike as a distinction without a difference, while adding complexity without benefit is always a bad idea. I suggest that you avoid having a learning experience and stick with raid1. I agree with you, it was only a theoretical question. Best regards keld - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: raid1 or raid10 for /boot
On Mon Feb 04, 2008 at 07:34:54AM +0100, Keld Jørn Simonsen wrote: I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? A plain RAID-10 does _not_ have a layout equivalent to RAID-1 and _cannot_ be used for booting (well, possibly a 2-disk RAID-10 could - I'm not sure how that'd be layed out). RAID-10 uses striping as well as mirroring, and the striping breaks both grub and lilo (and, AFAIK, every other boot manager currently out there). Cheers, Robin -- ___ ( ' } | Robin Hill[EMAIL PROTECTED] | / / ) | Little Jim says | // !! | He fallen in de water !! | pgp5z4BPWeOcx.pgp Description: PGP signature
Re: raid1 or raid10 for /boot
On Mon, Feb 04, 2008 at 09:17:35AM +, Robin Hill wrote: On Mon Feb 04, 2008 at 07:34:54AM +0100, Keld Jørn Simonsen wrote: I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? A plain RAID-10 does _not_ have a layout equivalent to RAID-1 and _cannot_ be used for booting (well, possibly a 2-disk RAID-10 could - I'm not sure how that'd be layed out). RAID-10 uses striping as well as mirroring, and the striping breaks both grub and lilo (and, AFAIK, every other boot manager currently out there). Yes, it is understood that raid10,f2 uses striping, but a raid10,near=2, far=1 does not use striping, anfd this is what you get if you just make amdadm --create /dev/md0 -l 10 -n 2 /dev/sda1 /dev/sdb1 best regards keld - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: raid1 or raid10 for /boot
On Mon Feb 04, 2008 at 12:21:40PM +0100, Keld Jørn Simonsen wrote: On Mon, Feb 04, 2008 at 09:17:35AM +, Robin Hill wrote: On Mon Feb 04, 2008 at 07:34:54AM +0100, Keld Jørn Simonsen wrote: I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? A plain RAID-10 does _not_ have a layout equivalent to RAID-1 and _cannot_ be used for booting (well, possibly a 2-disk RAID-10 could - I'm not sure how that'd be layed out). RAID-10 uses striping as well as mirroring, and the striping breaks both grub and lilo (and, AFAIK, every other boot manager currently out there). Yes, it is understood that raid10,f2 uses striping, but a raid10,near=2, far=1 does not use striping, anfd this is what you get if you just make amdadm --create /dev/md0 -l 10 -n 2 /dev/sda1 /dev/sdb1 Well yes, if you do a two-disk RAID-10 then (as I said above) you probably end up with a RAID-1 (as you do with a two-disk RAID-5). I don't see how this would work any differently (or better) than a RAID-1 though (and only serves to confuse things). If you have more than two disks then RAID-10 will _always_ stripe (no matter whether you use near, far or offset layout - these affect only where the mirrored chunks are put) and grub/lilo will fail to work. Cheers, Robin -- ___ ( ' } | Robin Hill[EMAIL PROTECTED] | / / ) | Little Jim says | // !! | He fallen in de water !! | pgpJkvfTSVpOK.pgp Description: PGP signature
raid1 or raid10 for /boot
I understand that lilo and grub only can boot partitions that look like a normal single-drive partition. And then I understand that a plain raid10 has a layout which is equivalent to raid1. Can such a raid10 partition be used with grub or lilo for booting? And would there be any advantages in this, for example better disk utilization in the raid10 driver compared with raid? best regards keld - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
