/debug dbg filesystem

[Robert Viduya]

>micah at flobb4.csd.sgi.com (Micah Altman) (micah at flobb4.csd.sgi.com, <1991Jan4.185158.16712 at odin.corp.sgi.com>):
> >I am interested in adding to /debug space to the /dev/usr partition.
> >I can umount the /debug partition but I can't figure out how to make
> >/dev/usr bigger. 
> 
> The /debug partition is not an actual file system, it 
> "provides an interface to running processes that may be used by debuggers 
> such as dbx" and " These files actually consume no
> disk space, and are only convenient handles by which a debugger can
> attach to a process. " so you don't need to move /debug to /dev/usr.
> 

I disagree with this statement.  While it's true that /debug is not a "real"
filesystem like /usr and /, it does represent a portion of disk known as
swap space.  If a system adminstrator wanted to, he could reduce the amount
of swap space and increase the amount of space for /usr by repartitioning the
disk.  A subsequent "df" will show an appropriate reduction of space in /debug
with a corresponding increase in /usr.

Doing something like this shouldn't be taken lightly however.  One needs to
know all the in's and out's of disk partitioning and one should be fully aware
of what the effects of reduced swap space will do to a system based on what
software is being run on that system.  As a general rule of thumb, I multiply
the amount of memory a system has by four to obtain the amount of swap space
to allocate for that system.  This works fairly well in most cases, but some
systems around here being used for scientific research require much more than
that.  For systems with lots of memory, a 1:4 ratio may be too much and a 1:2
or even a 1:1 ratio may be more appropriate.  It all depends on system load and
usage.

			robert
--
Robert Viduya					   robert at shangri-la.gatech.edu
Technical Services / Information Technology
Georgia Institute of Technology					 (404) 894-6296
Atlanta, Georgia	30332-0275