[Linux-cluster] A few GFS newbie questions: journals, etc

[Michael Conrad Tadpol Tilstra]

On Thu, Jun 09, 2005 at 03:31:50PM -0500, Nate Carlson wrote:
> yOn Thu, 9 Jun 2005, Jonathan E Brassow wrote:
> >Just a side thought...  Given that gulm uses quite a bit of memory, and 
> >the virtual machines will be using chunks as well.  It will be 
> >interesting to see how this plays out.
> 
> Got a crib sheet on expected memory needs for gulm?

gulm's memory usage is directly related to the number of locks it uses.
The number of locks used depends on what exactly you're doing with gfs.
So, the exact answer is that it depends.
Roughly, each lock uses 230 bytes.  Each hold on a lock uses about 80
bytes.  Each request to change the state of a holder on a lock is about
130 bytes.  Plus a bunch of static buffers.

Most simple setups I've seen use around 64M.  I've also seen setups use
nearly a gig of memory too. (not common) YMMV

-- 
Michael Conrad Tadpol Tilstra
If all you have is a hammer, everything looks like a nail.
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