Re: tmpfs?

[Henrique de Moraes Holschuh <hmh@debian.org>]

On Sun, 25 Jul 2004, Curt Howland wrote:
> What is "tmpfs"? Is it using any resources that would be better used 
> elsewhere? (Using Sid, 2.6.7)

tmpfs will keep everything in RAM.  It's disk storage backup is your swap
partitions.  Here, I keep /tmp in tmpfs (with a 512MB limit) and let it swap
to the 2GB disk partition if the system needs that RAM for something else.

The default limit for tmpfs is half your available RAM, I believe.  I have
no idea if it consumes its maximum capacity on virtual memory right away, or
if it alocates that as it needs more.  As for alocatting "real" memory
(RAM/swap), it does so only when there is something stored in that memory.

So an empty tmpfs probably doesn't ammount to anything worth worring about
on resource consumption in most configurations.

> Filesystem           1K-blocks      Used Available Use% Mounted on
> tmpfs                   257612         0    257612   0% /dev/shm

This is used for SYSV shared memory support.  I don't know of any
Debian-packaged apps that uses it (there are other ways to have
inter-process shared memory).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh