On Nov 18, 2015, at 9:49 PM, Devin Reade <gdr at gno.org> wrote: > > The one thing I would point out regarding the above link is that despite > conventional UNIX wisdom, *don't* put /usr on a separate filesystem > in CentOS 7. <sarcasm>Thank you RedHat</sarcasm> > > Flames to /dev/null. Sorry, you don’t get to throw that grenade and then run away. The old wisdom you refer to is simply obsolete, and it wasn’t Red Hat that made it so. ’Twas *progress* that made it so, specifically the fact that even a throwaway USB key has enough space to hold the complete OS on it these days. We no longer live in a world of 5 MB disk packs the size of extra large pizzas. Several OSes made /usr/{bin,lib} the same as /{bin,lib} way before Red Hat: Solaris, OS X, and Cygwin, at the least. Probably all of the embedded Linuxes, too. Even FreeBSD is starting to give up on /usr as separate from /. Although its installer still lets you put /usr into a separate slice, the boot process will break if you put it onto a different physical disk that the boot kernel can’t see, or use a different filesystem for it that isn’t compiled into the boot kernel. A truly “traditional” Unix OS wouldn’t have this problem: as long as the tools necessary to mount /usr are in /, it would be able to boot. If you disbelieve that, try installing FreeBSD 9.0 (i.e. pre-ZFS-boot) into a VM, then move /usr into a ZFS pool. It won’t even boot into single-user mode! Ask me how I know.