-info makes Mksquashfs write to stdout for every file it squashes, and
so yes, -info will probably slow things down if you've got lots of small
files, and stdout is throttled in some way (i.e. mksquashfs waits on
stdout).  Where is  the output of mksquashfs going?  If it's going to
the console then redirecting stdout to a file will probably speed things
up.  Unfortunately at the moment -info is the only way to discover what
Mksquashfs was doing prior to it hanging [1].

The -noappend option changing things is interesting but distinctly
perplexing.  If the Transparent Archivist deleted the output Squashfs
file before running Mksquashfs again then -noappend shouldn't make any
difference!   -noappend will only make a difference if Mksquashfs is
being run with a pre-existing file (i.e. the Transparent Archivist
hasn't deleted the previous output file).  But if that is happening it
is easy to see why things are going wrong, Squashfs will simply append
to the file, making it grow and grow, which is probably the exact
opposite behaviour expected. This isn't the first time that the default
Mksquashfs behaviour of Mksquashfs to append to the output file if it
exists has caused unexpected problems [2].

Until you discover otherwise, I'll assume -noappend fixes the
problem....

[1] I have long wanted to add a "post mortem" dump facility to
Mksquashfs, so in the case of a hung Mksquashfs, it will print out
exactly what Mksquashfs was doing when ^C is hit.  Maybe this year...

[2] This behaviour is entirely defensive and arguably the correct
behaviour - the alternative behaviour is to have Mksquashfs always
delete the output file if it exists (i.e. -noappend is default).
Unfortunately such an default action leads to all sorts of user
mistakes, where they specify the wrong file, and get their important
archived data deleted ...

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https://bugs.launchpad.net/bugs/722168

Title:
  mksquashfs hangs

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