Pascal Hambourg <pascal@xxxxxxxxxxxxxxx> writes: > Le 25/06/2022 à 19:10, Wols Lists wrote : >> On 25/06/2022 14:35, Stephan wrote: >>> >>> Does mdraid with metadata 1 work on the root filesystem w/o initramfs? > > No. Why would one not use an initramfs ? An initramfs adds unnecessary intransparency to the system. >> If you're using v1.0, then you could boot off of one of the mirror >> members no problem. >> >> You would point the kernel boot line at sda1 say (if that's part of >> your mirror). IFF that is mounted read-only for boot, then that's >> not a problem. > > Mounting read-only does not guarantee that there won't be any > write. See man mount(8) : > > -r, --read-only > Mount the filesystem read-only. A synonym is -o ro. > > Note that, depending on the filesystem type, state and kernel > behavior, the system may still write to the device. For example, ext3 > and ext4 will replay the journal if the filesystem is dirty. To > prevent this kind of write access, you may want to mount an ext3 or > ext4 filesystem with the ro,noload mount options or set the block > device itself to read-only mode, see the blockdev(8) command. Good point. Thus, there is no alternative to superblock 0.90 for root on mdraid w/o initramfs. This is the answer to the question why somebody (like me) may need to use superblock 0.90. >> Your fstab would then mount /dev/md0 as root read-write > > I don't think so. IME the root device in fstab is ignored, only the > options are used. This is some of the intransparency. Will the / entry in the /etc/fstab be copied to the initramfs to use it for mounting the real root filesystem? You imply that this is the case but the device will be ignored. Why? Gruß, -- Stephan
