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OS X breaks if I apply HFS compression to the whole volume. (It won't boot.)

What do I need to exclude?

I've been able to compress large parts of it, but then I had to restore after I compressed too much. I guess I can try to answer this via trial and error.

(Space is extremely tight on my boot volume.)

I'm guessing that these need to (or should) remain uncompressed:

/mach_kernel /sbin /dev  /bin /.??* /private

/private includes

 /etc /tmp /var 

I would guess I can get away with compressing most if not all of

/var/folders /System /Applications /Library /Users /usr

(Educated guess; include the stuff needed to bootstrap the system.)

At some point I may try to figure this out via trial and error, and answer my own question, but why reinvent the wheel when there's StackExchange?

share|improve this question
/var ought to be able to be compressed (it plays a vital role e.g. for Open Directory, but this happens relatively long after the root partition is mounted), while /S/L/CoreServices/boot.efi has to be accessible by the firmware. –  Ryccardo Apr 3 '13 at 22:04
Thanks. I'm not familiar with /usr/standalone, which includes /usr/standalone/i386/boot.efi but I would guess it shouldn't be compressed either. –  Matthew Elvey Apr 3 '13 at 22:08

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