Really big ramdisk: a bad idea?

[Net Llama!]

Before you go this route, are you sure that the bottleneck is memory?  If
you look at the output from free, is it all consumed?  What about in top,
how much of the memory is it using?

On Thu, 12 Sep 2002, Kevin O'Gorman wrote:

> I've got a database build that runs for 12 hours on my old machine, and
> I have to do this more often than I like.  It's getting longer too.
> The database is gdbm, there are about 2 million records of roughly
> 100 bytes each (average; most are shorter, a few are longer).
> While it runs, top(1) reports the process using less than 10% of
> the CPU, so I assume the bulk of the time is in paging the database.
> The current machine is maxed out at 256MB RAM, and the database is
> itself about that size, so it's not all fitting in the Linux buffer
> cache.
>
> I'm getting a machine online with 2GB DDR RAM, and I'm thinking of
> performing this build in a really big RAMDISK.  Does this make sense?
> First of all, can you build and tear down such a thing without needing
> a reboot?  Second, do accesses to the ramdisk get put in the Linux
> buffer cache, and would this cause a problem?  Can anyone see a
> reason this shouldn't work and speed up the build roughly 10x?
>
> ++ kevin
>
>

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lonni J Friedman				netllama at linux-sxs.org
Linux Step-by-step & TyGeMo		     http://netllama.ipfox.com