Apache/mod_cache: "Error 103 Software caused connection abort"
I've seen the error message:
[error] (103)Software caused connection abort: cache: error returned while trying to return disk cached data
before in two situations, both which involved file-system problems (as the message itself kindof implies) One was a situation where the partition holding the cache was full. the caches grow really fast, and well, it ended up filling the partition. The other time the filesystem itself was damaged.
The error implies that its a read problem, but it can be a write problem too.
Root cause: your filesystem
Proposed solution: Check the integrity of the filesystem, and if that checks out, move the cache to a bigger partition or bigger disk, and you should be okay.