Re: autofs illustrations

[Peter Staubach <staubach@redhat.com>]

Fletcher Mattox wrote:
> Jeff Moyer writes:
>
>   
>> http://people.redhat.com/jmoyer/autofs_linux_kongress.pdf
>>     
>
> Jeff,
>
> Nice paper.  Thanks!  I'm suffering from RPC port exhaustion (you
> responded to one of my queries last week), so I am especially interested
> in your section on port allocation.  You state
>
> 	When a service requests an RPC connection, binding to
> 	a reserved port is the default.  The RPC layer scans
> 	ports starting from 800 down until it finds one that
> 	is unallocated.
>
> My experience is that the 2.6.17.4 kernel allocates between 512 and 1024
> and then begins with unreserved ports >33000.  Yeah, I know.  It's just
> a nit, but I thought I'd tell you anyway.
>
> The most interesting part of the paper was the comment about a practical
> limit of 100 mounts in rapid succession.  I am certain this is the limit
> we have bumped into.  Do you see any improvement in this in autofs 5?
>
> Unprivileged ports and/or UDP are not viable options for us, so I am
> forced to increase the timeout from 5 minutes to 24 hours, which in
> practice means they are always mounted.  We have about 400 automounted
> filesystems, so the only long term solution for us is to try to coalesce
> them to less than 100.  Very painful.

You have 400 automounted file systems, all of which need to be mounted at
the same time?  If so, I might suggest that static mounts might better serve
your needs.  Or, rethink the application and deployment.

    Thanx...

       ps