I am doing some clean-up and restructuring of my OS, and I've been wondering:

- How important is the /var directory in a desktop installation? Suppose I mount it in an XFS filesystem (known for corrupting data easily) or in an EXT2 partition (no journal), and never do any backups of that one partition, what kind of woes can I have if that entire partition ever goes kaput for any given reason?

- Does /boot have to remain mounted after the system is running? Isn't the kernel loaded and kept in memory? Really, I have no idea. Or, if it's really necessary all the time, can it be mounted read-only in fstab? Ubuntu mounts it rw, but maybe because it's assumed to be in the same partition as / where lots of things have to be rw.

TIA

Are you asking if either of those need to be put on their own partitions? No, they don't.

If you are asking if those directories need to exist, then yes they do.

Of course they need to exist, I am not THAT much of a newbie. What I want to know is, what is likely to stop working if I get a corrupted /var partition? And, can I unmount /boot after the system is running, and can I mount it read-only in the first place?

A corrupted /var is likely to be pretty disastrous. Daemons may behave unpredictably if they are unable to write/access their log files, some distributions (like Slackware for instance) keep their package information under /var, and information about running processes is kept under /var/run.

I suppose you could remount /boot after the system starts, but there is no need for it to be on it's own partition in the first place (not since the early PC days anyway).

I formatted my / partition as EXT4. I've read that may cause problems with older kernels, or GRUB, or something. So I made a separate EXT2 /boot partition.

Not saying you shouldn't unmount /boot (but you shouldn't unmount /var), but what do you hope to gain by doing so?
--- rod.

I expect to drastically reduce the possibility of the kernel/boot files getting damaged by any kind of incident.

Looks like my question has been answered: I made the separate boot partition and it is not mounted anyway, although it is present in fstab. Solved.

Thank you.