/proc filesystem in AIX

Question

This question is in context of AIX (5.3) On what basis does space gets allocated for whatever needs to be stored under the virtual filesystem /proc

Does the OS grabs space from / ? For instance I have :

Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/hd4           0.25      0.08   70%    10983    38% /
/proc                 -         -    -         -     -  /proc

So what will happen if my / gets used up to 99%? Where will proc get its space?

Or do I have it all wrong ? Is /proc just a representation of server memory ?

Answer 1

Or do I have it all wrong ? Is /proc just a representation of server memory ?

Yes :) It's server memory, kernel to be specific.

/proc is filesystem driver that sees kernel memory structures instead of disk. It never uses disk space, well, other than the device driver on disk.

It's a way of making kernel data structures easily readable by user level code. It uses the filesystem, the "everything is a file" metaphor that UNIX helped pioneer. Then you can use the same tools (syscalls, command line tools) to read and write this kernel data that you normally use, instead of specific commands or complicated calls like ioctl().

Answer 2

I have no AIX experience, but all every OS I used (BSD, Linux) /proc is a virtual filesystem. It does not use any real disk space.