"Tony Sceats" <[EMAIL PROTECTED]> writes:
> Ah, now this all depends. If /var/run was a normal disk filesystem
> under Ubuntu you would be correct. It isn't, though:
>
> ] mount | grep /var/run
> varrun on /var/run type tmpfs (rw,noexec,nosuid,nodev,mode=0755)
>
> Note 'type tmpfs' there? tmpfs is a swap backed ramdisk, essentially,
> and like /var/lock is put there by Ubuntu to ensure that these
> directories are cleaned at reboot without having to fuss about deleting
> files or read-only filesystems.
>
> hey, that's pretty cool, can't say I'm familiar with tmpfs - does it
> pre-allocate the space or grow to the specified size as it needs to?
Like ramfs it grows on demand, with a cap, rather than preallocating
space. ramdisk is a reasonably inaccurate description of it, really,
because this is a purpose built ram backed filesystem rather than
emulating a block device.
> I ask because clearly 2Gb is an enormous amount of RAM/SWAP to spend
> on /var/run just so you don't have to clean it at boot time (which can
> be done trivially)
Heh, yes: it would be.
>> imho, 2Gb is either way too big or too small depending on what the computer
>> does.. try 'du -hs /var/run/*' to see what else is happening there - for me
>> it's usually less than 1Mb, but sometimes spools (eg, mail spools) will be
>> put there which will increase it a lot,
>
> The mail spool lives under /var, but not under /var/run. The FHS, in
> fact, carefully defines the purpose of /var/run -- and that does not
> include being scratch space for large processes.
>
> FHS aside (because I know you're right about it), I know I've seen
> spools there, there used to pretty much always be a /var/run/spool
> directory, and I know this has caused me problems, many moons ago now
> though, that's for sure, probably on RH6 or Debian Potato
Well, people do all sorts of crazy stuff, I guess. I am not familiar
with any Unix that stuck spools under /var/run, but someone must have:
every /other/ sort of perversion has been tried by some Unix vendor or
others at some time.
> Y'all should file a bug report indicating that Mondo should use /tmp or
> /var/tmp to build big scratch files.
>
> Indeed, this would be very annoying, space aside - I'm not actually
> familiar with this app, but given the in-built inpermanence of
> /var/run, this seems like a very quick way to lose hours of hard work!
Mmmm. Using a tmpfs there is reasonably new, and not yet popular, so on
most distributions /var/run is backed on the same media as the rest of
/var, for better or worse.
Regards,
Daniel
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