swap sizing in a kickstart script
Gerrard Geldenhuis
Gerrard.Geldenhuis at datacash.com
Fri Jan 11 16:32:09 UTC 2008
Just read this which clarified it for me:
BTW, with overcommit_memory=2,
CommitLimit = (MemTotal * (overcommit_ratio / 100)) + SwapFree
With the default of overcommit_ratio = 50, this simplifies to:
CommitLimit = (MemTotal / 2) + SwapFree
Unless you're setting overcommit_ratio to 100, this means that with
640MB of RAM and no swap, user programs are allowed to request 320MB of
memory at most.
I hope this helps...
> -----Original Message-----
> From: kickstart-list-bounces at redhat.com [mailto:kickstart-list-
> bounces at redhat.com] On Behalf Of Gerrard Geldenhuis
> Sent: 11 January 2008 15:51
> To: squid at oranged.to; Discussion list about Kickstart
> Subject: RE: swap sizing in a kickstart script
>
> Hi
> I don't completely understand it but you have to set your overcommit
> ratio in the kernel to match you swap space
>
> Percentage of physical memory size to include in overcommit
> calculations.
>
> Memory allocation limit = swapspace + physmem * (overcommit_ratio /
100)
>
> swapspace = total size of all swap areas
> physmem = size of physical memory in system
>
> cat /proc/sys/vm/overcommit_ratio
>
> Unless I have the wrong end of the stick, then please correct me.
>
> I understood overcommit ratio to be the amount of swap space expected
as
> a ratio of the amount of ram but after reading up on it again I don't
> think I understand it anymore.
>
> Apologies for complicating your answer.
>
> Regards
>
> > -----Original Message-----
> > From: kickstart-list-bounces at redhat.com [mailto:kickstart-list-
> > bounces at redhat.com] On Behalf Of Jimmy Stewpot
> > Sent: 11 January 2008 15:39
> > To: squid at oranged.to; Discussion list about Kickstart
> > Subject: Re: swap sizing in a kickstart script
> >
> > Hi All,
> >
> > Jimmy Stewpot wrote:
> > > Hello,
> > >
> > > Is there an automated way in the kickstart file for the system to
> > > automatically create the "redhat recommended" swap size?
> > >
> > > Regards,
> > >
> > > Jimmy
> > >
> > > _______________________________________________
> > > Kickstart-list mailing list
> > > Kickstart-list at redhat.com
> > > https://www.redhat.com/mailman/listinfo/kickstart-list
> >
> > It seems that there is a --recommended variable in the code which
will
> > do it. After seeing that I found it in the redhat documentation
> >
> > http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/en-
> > US/RHEL510/Installation_Guide/s1-kickstart2-options.html
> >
> > Search for --recommended
> >
> > Regard
>
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