Messages in this thread | | | Date | Sun, 14 Feb 2010 21:47:16 +0100 | From | Asdo <> | Subject | Re: Linux mdadm superblock question. |
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Henrique de Moraes Holschuh wrote: > On Sat, 13 Feb 2010, Michael Evans wrote: > >> I remember hearing that 1.x had /no/ plans for kernel level >> auto-detection ever. That can be accomplished in early-userspace >> leaving the code in the kernel much less complex, and therefore far >> more reliable. >> > > Yes, it is far more reliable kernel side, if only because it doesn't do > anything. > > But the userspace reliability is _not_ good. initrds are a source of > problems the moment things start to go wrong, and that's when they are not > the problem themselves. > > And the end result is a system that needs manual intervention to get its > root filesystem back. > > In my experience, every time we moved critical codepaths to userspace, we > ended up decreasing the *overall* system reliability. > I don't see it like this. You have the same chance to screw up the system by making mistakes in the files in /etc, in the networking config, the firewall, the server applications... (note: I speak for Debian/Ubuntu, redhat's initramfs I think is more messy.) 1.x autodetection worked great for me in initramfs. Basically you only need /etc/mdadm/mdadm.conf copied to initramfs (via update-initramfs), the rest is done by Debian/Ubuntu standard initramfs procedure. Also consider 1.x allows to choose which arrays are autoassembled (hostname written in the array name equal to hostname in the machine or specified in mdadm.conf): this is more precise than 0.9 which autoassembles all, I think.
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