# gmirror mount operation not supported by device



## lifanov (Feb 4, 2010)

I have a not-so-sophisticated install of FreeBSD on a gmirror of two hard drives. The underlying fs is UFS2 with soft updates.
But I can't mount anything useful (specifically: unionfs, nullfs, linproc) on it. I can mount msdosfs.
I run many FreeBSD systems, but this is the only one with gmirror, so I ask: is it a gmirror deficiency or did I break something?


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## OH (Feb 4, 2010)

You should really give some more info here. Like [cmd=]df[/cmd]'s output, the command that fails and the error message that goes with the failure.


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## lifanov (Feb 4, 2010)

Alright, `# df -h` before `# rm -r /boot/kernel && mv /boot/kernel{.old,}`

```
lifanovbsd0# df -h
Filesystem            Size    Used   Avail Capacity  Mounted on
/dev/mirror/gm0s1a    496M    491M    -34M   108%    /
devfs                 1.0K    1.0K      0B   100%    /dev
/dev/mirror/gm0s1e    496M     46K    456M     0%    /tmp
/dev/mirror/gm0s1f    667G     20G    593G     3%    /usr
/dev/mirror/gm0s1d    4.8G    184M    4.3G     4%    /var
/dev/da0p2            931G    265G    666G    28%    /mnt
/dev/da0p2            931G    265G    666G    28%    /mnt
lifanovbsd0#
```
after

```
lifanovbsd0# df -h
Filesystem            Size    Used   Avail Capacity  Mounted on
/dev/mirror/gm0s1a    496M    251M    205M    55%    /
devfs                 1.0K    1.0K      0B   100%    /dev
/dev/mirror/gm0s1e    496M    122K    456M     0%    /tmp
/dev/mirror/gm0s1f    667G     19G    595G     3%    /usr
/dev/mirror/gm0s1d    4.8G    184M    4.3G     4%    /var
/dev/da0p2            931G    265G    666G    28%    /mnt
lifanovbsd0#
```

Command that fails:

```
lifanovbsd0# mkdir one two
lifanovbsd0# mount_unionfs one two
mount_unionfs: /root/two: : Operation not supported by device
lifanovbsd0#
```

Same deal is with nullfs and linprocfs.

Side question: moving kernel directory to free up space was the last thing I did. Is that safe?


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## lifanov (Feb 4, 2010)

Wow, this was my stupid.
The kernel modules had version mismatches and rebooting with the old kernel fixed everything.


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