Hi, 在 2025/7/16 22:30, Filipe Maia 写道:
Hi, When a 4Kn disk is added to an mdadm array with sector size 512, its sector size changes to 4096 to accommodate the new disk. Here's an example: ``` truncate -s 1G /tmp/loop512a truncate -s 1G /tmp/loop512b truncate -s 1G /tmp/loop512c truncate -s 1G /tmp/loop4Ka losetup --sector-size 512 --direct-io=on /dev/loop0 /tmp/loop512a losetup --sector-size 512 --direct-io=on /dev/loop1 /tmp/loop512b losetup --sector-size 512 --direct-io=on /dev/loop2 /tmp/loop512c losetup --sector-size 4096 --direct-io=on /dev/loop3 /tmp/loop4Ka mdadm --create /dev/md2 --level=5 --raid-devices=3 /dev/loop[0-2] # blockdev returns 512 blockdev --getss /dev/md2 mdadm /dev/md2 -a /dev/loop3 mdadm /dev/md2 -f /dev/loop2 # blockdev still returns 512 blockdev --getss /dev/md2 mdadm -S /dev/md2 mdadm -A /dev/md2 /dev/loop0 /dev/loop1 /dev/loop3 # blockdev now returns 4096 blockdev --getss /dev/md2 ``` This breaks filesystems like XFS, with new mounts failing with: `mount: /mnt: mount(2) system call failed: Function not implemented.`
Yes, this is a known problem. Li Nan was trying to fix this long time ago.
Shouldn't the user be warned when this can happen?
Kernel should forbid larger lbs new disk, however, this is still a missing feature for now. Thanks, Kuai
Cheers, Filipe
