Linux mdadm superblock question.
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From: Justin Piszcz on 11 Feb 2010 18:10 Hi, I may be converting a host to ext4 and was curious, is 0.90 still the only superblock version for mdadm/raid-1 that you can boot from without having to create an initrd/etc? Are there any benefits to using a superblock > 0.90 for a raid-1 boot volume < 2TB? Justin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Michael Evans on 11 Feb 2010 21:00 On Thu, Feb 11, 2010 at 3:00 PM, Justin Piszcz <jpiszcz(a)lucidpixels.com> wrote: > Hi, > > I may be converting a host to ext4 and was curious, is 0.90 still the only > superblock version for mdadm/raid-1 that you can boot from without having to > create an initrd/etc? > > Are there any benefits to using a superblock > 0.90 for a raid-1 boot volume > < 2TB? > > Justin. > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo(a)vger.kernel.org > More majordomo info at �http://vger.kernel.org/majordomo-info.html > You need the superblock at the end of the partition: If you read the manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also NOT 1.2; those use the same superblock layout but different locations). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: martin f krafft on 13 Feb 2010 02:00 also sprach Justin Piszcz <jpiszcz(a)lucidpixels.com> [2010.02.12.1200 +1300]: > I may be converting a host to ext4 and was curious, is 0.90 still the > only superblock version for mdadm/raid-1 that you can boot from > without having to create an initrd/etc? > > Are there any benefits to using a superblock > 0.90 for a raid-1 boot > volume < 2TB? FYI: http://bugs.debian.org/492897 -- martin | http://madduck.net/ | http://two.sentenc.es/ it may look like i'm just sitting here doing nothing. but i'm really actively waiting for all my problems to go away. spamtraps: madduck.bogus(a)madduck.net
From: H. Peter Anvin on 13 Feb 2010 15:00 On 02/11/2010 05:52 PM, Michael Evans wrote: > On Thu, Feb 11, 2010 at 3:00 PM, Justin Piszcz <jpiszcz(a)lucidpixels.com> wrote: >> Hi, >> >> I may be converting a host to ext4 and was curious, is 0.90 still the only >> superblock version for mdadm/raid-1 that you can boot from without having to >> create an initrd/etc? >> >> Are there any benefits to using a superblock > 0.90 for a raid-1 boot volume >> < 2TB? >> >> Justin. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo(a)vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > You need the superblock at the end of the partition: If you read the > manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also > NOT 1.2; those use the same superblock layout but different > locations). 0.9 has the *serious* problem that it is hard to distinguish a whole-volume However, apparently mdadm recently switched to a 1.1 default. I strongly urge Neil to change that to either 1.0 and 1.2, as I have started to get complaints from users that they have made RAID volumes with newer mdadm which apparently default to 1.1, and then want to boot from them (without playing MBR games like Grub does.) I have to tell them that they have to regenerate their disks -- the superblock occupies the boot sector and there is nothing I can do about it. It's the same pathology XFS has. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Justin Piszcz on 13 Feb 2010 15:10
On Sat, 13 Feb 2010, H. Peter Anvin wrote: > On 02/11/2010 05:52 PM, Michael Evans wrote: >> On Thu, Feb 11, 2010 at 3:00 PM, Justin Piszcz <jpiszcz(a)lucidpixels.com> wrote: >>> Hi, >>> >>> I may be converting a host to ext4 and was curious, is 0.90 still the only >>> superblock version for mdadm/raid-1 that you can boot from without having to >>> create an initrd/etc? >>> >>> Are there any benefits to using a superblock > 0.90 for a raid-1 boot volume >>> < 2TB? >>> >>> Justin. >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >>> the body of a message to majordomo(a)vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> >> You need the superblock at the end of the partition: If you read the >> manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also >> NOT 1.2; those use the same superblock layout but different >> locations). > > 0.9 has the *serious* problem that it is hard to distinguish a whole-volume > > However, apparently mdadm recently switched to a 1.1 default. I > strongly urge Neil to change that to either 1.0 and 1.2, as I have > started to get complaints from users that they have made RAID volumes > with newer mdadm which apparently default to 1.1, and then want to boot > from them (without playing MBR games like Grub does.) I have to tell > them that they have to regenerate their disks -- the superblock occupies > the boot sector and there is nothing I can do about it. It's the same > pathology XFS has. > > -hpa > My original question was does the newer superblock do anything special or offer new features *BESIDES* the quicker resync? Justin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |