Freebsd – Mount /dev/shm in FreeBSD jail

devfreebsd

I would like to mount /dev/shm in a freebsd jail. Every time I attempt to, I get these errors:

[root@gaming /]# mount -t tmpfs tmpfs /dev/shm
mount: /dev/shm: No such file or directory
[root@gaming /]# touch /dev/shm
touch: /dev/shm: Operation not supported
[root@gaming /]#

Jail works perfectly, I just can't figure out how to get devfs to automagically create a directory.

Thanks.

Best Answer

If you want to use tmpfs inside jail it is better to add line like

tmpfs /jails/foo.example.org/tmp tmpfs rw,size=524288000 0 0

to the jail's fstab file.

Related Solutions

Freebsd – I am going to chop the FreeBSD automounter into little pieces and boil them in oil

Why, hello there Lars! That's a fascinating question you've asked, and after some research I may have found an answer for you.

According to this and other posts out there, it may be possible to set the VFCF_JAIL attribute on the NFS filesystem provider, which would in theory allow jails to perform NFS mounts. This may, in turn, allow one to run amd inside the jail...which would neatly solve this issue.

I'll try rebuilding the kernel this evening to see how things work out. It's not necessarily the greatest solution (since it means you need to make sure this change persists across future kernel updates), but it would be interesting if it works.

And remember...

           ___________    ____                                           
    ______/   \__//   \__/____\                             
  _/   \_/  :           //____\\                             
 /|      :  :  ..      /        \                         
| |     ::     ::      \        /                             
| |     :|     ||     \ \______/     Don't try to rebuild the
| |     ||     ||      |\  /  |        kernel remotely because
 \|     ||     ||      |   / | \         you know you're just
  |     ||     ||      |  / /_\ \        going to hose the server.
  | ___ || ___ ||      | /  /    \    
   \_-_/  \_-_/ | ____ |/__/      \   
                _\_--_/    \      /   
               /____             /  
              /     \           /    
              \______\_________/

ZFS on FreeBSD – Recovery from Data Corruption

The problem was that the new motherboard's BIOS created a host protected area (HPA) on some of the drives, a small section used by OEMs for system recovery purposes, usually located at the end of the harddrive.

ZFS maintains 4 labels with partition meta information and the HPA prevents ZFS from seeing the upper two.

Solution: Boot Linux, use hdparm to inspect and remove the HPA. Be very careful, this can easily destroy your data for good. Consult the article and the hdparm man page (parameter -N) for details.

The problem did not only occur with the new motherboard, I had a similar issue when connecting the drives to an SAS controller card. The solution is the same.

Best Answer

Related Solutions

Freebsd – I am going to chop the FreeBSD automounter into little pieces and boil them in oil

ZFS on FreeBSD – Recovery from Data Corruption

Related Topic