Memory based tmp - advantages?

[chavez243ca]

is there any advantage - or disadvantage for that matter - in having a RAM-based /tmp?

 

[fronclynne]

Pro:

• It's very fast
• It doesn't get crufty, since nothing survives a reboot
• It puts otherwise unused memory/swap to use
• To make more space in /tmp you just need to reconfigure and remount (no tedious mucking about with on-disk filesystems)

Con:

1. Nothing survives a reboot, even the stuff you wanted to temporarily keep
2. If you have 1G in /tmp and you fill it up, that's 1G of memory/swap you might want for something else
3. If you decide you don't like it, you're going to have to find some space to put a real filesystem for /tmp

That said, I've been using tmpfs(5) on an old laptop for a couple of weeks without any problems (and before that I was using tmpmfs="YES" in rc.conf(5)).

 

[vermaden]

[*]It doesn't get crufty, since nothing survives a reboot

This can be also achieved with clear_tmp_enable="YES" in /etc/rc.conf

[*]Nothing survives a reboot, even the stuff you wanted to temporarily keep

This is the PROPER behaviour of /tmp, if you want temporary things to survive reboot, you store them in /var/tmp, that the difference between them.

 

[phoenix]

/var/tmp is where you should be storing temp files you want to access after a reboot. By definition, /tmp should be cleared at every boot.

 

[fronclynne]

/var/tmp is where you should be storing temp files you want to access after a reboot. By definition, /tmp should be cleared at every boot.

You're talking procedure vs. behaviour & further /tmp policy is subject to local administrator's whims.

My point was that a memory or swap based /tmp will not persist regardless of policy (unless it has a backing file).