When I do:
ls -a /
on Fedora 21 there is a hidden file named:
.readahead and it's 104092k
What is this file?.... is it suppose to be there?
I found this on google:
readahead is a system call of the Linux kernel that loads a file's contents into the page cache, providing that way a file prefetching technology. When a file is subsequently accessed, its contents are read from the main memory (RAM) rather than from a hard disk drive (HDD), resulting in much lower file access latencies due to much higher performance of the main memory.
readahead() initiates readahead on a file so that subsequent reads from that file will be satisfied from the cache, and not block on disk I/O (assuming the readahead was initiated early enough and that other activity on the system did not in the meantime flush pages from the cache).
The only hit for this particular file was this mailing-list:
Indeed those files appear to be misplaced, the .config directory look like a leftover from the installation.. and the .readahead file appears to be written at boot time, dunno what writes it, monitoring it with "audit" may yield some clues.
File a bug report.