Re: Linux RAM drive support/performance
"Paul McHale" <pmchale@doubleesolutions.com> writes:
> Does Linux support any RAM drive(s)? How much faster are these drives over
> an attached drive? Is there a CPU performance penalty?
>
> We would like to replace our mechanical drive with a small (<4GB) RAM drive.
> The mechanical drive is getting pounded 24 hours a day. In addition to
> fatigue, the extra performance would be nice.
The general wisdom is that it's a waste of memory using it for a RAM
disk. Generally, it's better to buy the RAM and let the OS decide how
to use it for file-system caching. Of course this is in general, and
there may well be specific applications that would benefit.
If you do use a RAM disk I doubt there's much of a CPU performance
hit, other than the fact that, if the RAM disk is actually utilized,
the CPU will not have much idle time because it's not waiting on disk
I/O. Of course the same applies to a good caching scheme.
4G is really NOT small. Maybe in terms of disk space, but that's still
a lot of RAM!
> Is it true the x86 architecture is limited to 32 bit addressing and will
> never support more than 4GB of address space? Trying to see what the
> limitation will be.
Actually I think that the Pentium line of processors actually has a
36bit MMU, for 64G of addressable memory. Last time I checked both
Windows and Linux could use all that memory.
> I know this is a lot of questions. As always, any help is appreciated.
Good Luck!
Gary
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