I can't post a quick solution to the problem, but I can give some tips to prevent it.
My root was full a few days ago. It was mainly because of Squid, but logfiles also can cause the problem. My server did not start anymore.
If you are going to install Zentyall, DO NOT use the automated harddisk setup. You'll end up with a very small root (in my case 7GB) that fills up in no-time and the home gets all the space you'll likely never use.
One day your server will freeze, and at reboot it just won't start.
Zentyal is using lvm2 (Logical Volume Manager 2) for the automated hd setup.
If you see /dev/mapper/ it means that your setup uses the LVM2 scheme.
In that case what you can do is resize the root volume, that's where all the important stuff is.
Zentyal LVM2 setup only uses 3 volumes:
- root = all the important stuff
- swap = only used as a kind of swap memory, not for storage
- home = for user files and samba stuff
The /boot volume is NOT part of the LVM2 scheme, you can see it like /dev/sda1.
Don't be confused about hda and sda, it just IDE harddisk or SATA / SCSI harddisk.
Leave swap alone.
Check how much space is used for /home. You have to take some space from /home and give it to /root.
You'll have to shrink /home, after that expand /root to use that free space.
Now the bad news:
1. You will have to learn the LVM2 partitioning scheme. Search on the web.
2. Resizing is done from the Ubuntu live CD WITHOUT mounting the volumes.
3. Each resize operation has two steps, resizing the volume AND the file system. If you do it wrong, you will LOOSE your /home volume and will have to recreate it (I screwed it).
4. Do NOT use Gparted. It doesn't support LVM2 yet.
5. Do not use the graphical interface "system-config-lvm" as it will wipe out the whole VG.
In some cases you might just start over all again and choose manual hd setup.
I find it a mayor flaw that Zentyal/Ubuntu automatic setup uses such a smal root.
Some commands you can use from commandline:
df lists the filesystems and used/available space. Start here to see what is full.
pvdisplay lists the physical volume, you can see this as a partition
vgdisplay lists details about the volume group like name, allocated/available space. A volume group can hold one or more partitions, they can sit on different hd's.
lvdisplay lists the logical volumes inside the volume group. On a default install, /root, /swap and /home will be listed.
What can you do to avoid filling your /root?
1. Relocate the Squid cache. I had the cache set to 6GB while my /root was 7GB. Stupid but I learned.
2. Logfiles are being renamed first, then compressed. You might try and delete the gzipped log files, but Zentyal itself has an option to purge logs. Anyway, it has been recommended to rotate logs more aggressively.
Should we better not use LVM2 partitioning scheme but the normal one instead?
No. I do think that LVM2, once mastered, will be way more easier to manage volumes. It has a learning curve but in the long run it makes adding hd's a snap. Imagine just adding a new harddisk to your system and extending your root volume to use that space?
I'm surprised that there is so little input from Zentyal staff on these kind of problems. Sometimes we need just a little guidance, it's hard enough already coming from Windows.
Cheers.