Why do I get "No space left on device" when running mail

Question

First of all I've checked these two solutions on serverfault but I'm still having issues.

Here's my problem:

root@myserver:/# mail
/tmp: No space left on device

• Firstly I checked the filesystem usage by running df -k but all filesystem usage was under 25%
• Then I ran df -i to check inode usage; maximum was 4% usage
• I have emptied /tmp and /var/tmp and still get above error

Pertinent information:

• I'm running Debian 6, postfix
• Recently had to remove a number of rogue scripts which were planted in user www directories. They looked like this: https://stackoverflow.com/questions/3328235/how-does-this-giant-regex-work these were being used to send high volumes of spam, and I've checked the mail logs and mail queue to ensure spam is no longer being sent. As a result, mail logs had grown very quickly. I have archived the large mail logs to another machine / deleted them, and done the same with all other large files in /var/log

Here's the output of df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda              20G  4.0G   15G  22% /
tmpfs                 249M     0  249M   0% /lib/init/rw
udev                   10M  112K  9.9M   2% /dev
tmpfs                 249M     0  249M   0% /dev/shm
overflow              1.0M     0  1.0M   0% /tmp

Solution

overflow              1.0M     0  1.0M   0% /tmp

You have only 1 MB of tmp space

EDIT:

In this way you can increase size of /tmp

sudo dd if=/dev/zero of=/usr/temp-disk bs=2M count=1024
sudo mke2fs -j /usr/temp-disk
sudo mke2fs -j /usr/temp-disk
sudo chmod 1777 /usr/temp-disk
sudo umount /tmp
sudo mount -t ext3 -o rw,noexec,nosuid,loop /usr/temp-disk /tmp
df -h

Comments

[hazymat]

Yeh - having problems with the mini-markdown in the comment box, newlines not allowed...

[MadHatter]

hazymat, edit it into your question instead.

[hazymat]

@MadHatter Just trying to edit into the original question but formatting / tabs not lining up - give me a few secs...

[hazymat]

@MadHatter Done :)

[David Schwartz]

Your /tmp has switched to overflow. Do you have a /etc/init.d/mountoverflowtmp script? See the documentation. Do you have sufficient swap?

[hazymat]

Thanks. I realised now mail is not part of postfix, I was just including the fact I run postfix as an aside. I don't have issues with the MTA itself, just the mail client.

[hazymat]

Thank you. I see your point - 1MB available space is not enough to run mail. How did it get that way? Can a filesystem mount automatically shrink if another requires more space? Sorry for the basic question. It's just that I never changed the available space myself, and mail always used to work.

[Suku]

See my edit in answer. In that way you can increase /tmp space

[Suku]

Re: FS size; no, filesystem will not get shrink, although there are exceptional cases. In your case, asfaiu, increasing the size of /tmp will fix the issue.

[adaptr]

I'll edit the tags.

[David Schwartz]

@hazymat: To answer the "how did it get that way" question, see this page.

[hazymat]

David. Thanks so much for providing that link. Very interesting to learn.