[STDERR] Output file write error --- out of disk space?

[Sindre]

Hello,

Recently, I have noticed a lot of these entries in the stderr.log file:

2011-09-09 15:04:40.274 [STDERR] Output file write error --- out of disk space?
2011-09-09 15:12:13.629 [STDERR] Output file write error --- out of disk space?
2011-09-09 15:12:13.657 [STDERR] Output file write error --- out of disk space?

I am not sure how to interpret this error. What exactly is trying to write to disk and to where?

As you can see below, all partitions on the server has plenty of free space:

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda1 1486080 707444 701928 51% /
/dev/sda7 200263500 112182000 77744480 60% /home
/dev/sdb1 75700148 22139548 49653192 31% /home2
/dev/sda3 15872636 3324156 11729168 23% /var
/dev/sda2 15872636 5107624 9945700 34% /usr
/dev/sda6 1019208 62352 904248 7% /tmp
tmpfs 3052448 0 3052448 0% /dev/shm

I appreciate any suggestions!

[webizen]

try 'df -ih' to see inode usage.

[Sindre]

Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/sda1 375K 18K 357K 5% /
/dev/sda7 50M 3.8M 46M 8% /home
/dev/sdb1 19M 53K 19M 1% /home2
/dev/sda3 4.0M 9.7K 4.0M 1% /var
/dev/sda2 4.0M 168K 3.8M 5% /usr
/dev/sda6 258K 13K 245K 5% /tmp
tmpfs 746K 1 746K 1% /dev/shm

[webizen]

any disk partition becomes read-only? you may do sth like 'touch 1' to check.

[Sindre]

No, I have not made any changes to the partitions. Here is the content of /etc/fstab:

LABEL=/                 /                       ext3    defaults,usrquota               1 1
LABEL=/home             /home                   ext3    defaults,noatime,usrquota       1 2
LABEL=/home2            /home2                  ext3    defaults,noatime,nodev          1 2
LABEL=/var              /var                    ext3    defaults,usrquota               1 2
LABEL=/usr              /usr                    ext3    defaults,usrquota               1 2
devpts                  /dev/pts                devpts  gid=5,mode=620                  0 0
sysfs                   /sys                    sysfs   defaults                        0 0
proc                    /proc                   proc    defaults                        0 0
LABEL=SWAP-sda5         swap                    swap    defaults                        0 0
LABEL=/tmp              /tmp                    ext3    noexec,nosuid                   1 2
/tmp                    /var/tmp                ext3    noexec,nosuid                   0 0
tmpfs                   /dev/shm                tmpfs   noexec,nosuid,nodev             0 0

[mistwang]

Not likely is a disk space issue. Should be something else.
google results indicates that is an issue with libjpeg.
If you can reproduce this error, you just strace the PHP process producing the error to find out why.