On Thu, 14 Feb 2008, Scott Lawrence wrote:
> Is there a way to set up a RAM disk under hpcmips
NetBSD? Perhaps something
> like 1meg big (or auto expanding... either way)
>
> I looked around and found some information about making
an install image
> that sits in ram, but not really a live, usable,
mountable partition after
> boot... or perhaps i'm on crack and not reading things
through correctly.
>
> On the z50, disk access to the CF card is pretty
painful (PIO), and it'd be
> nice to have the source code and project directory i'm
working on be in a
> RAM disk, perhaps like 1meg or so big, then just
manually flush changes to
> the CF card manually...
>
>
>
> I've been using BSD for about 17 years, but I'm only
just now getting really
> into the details of maintaining and using my own
machine.
The simplest option is probably to mount a tmpfs
filesystem and
copy the files you want to it, then copy things back when
done.
eg:
# mkdir /ramdisk
# mount -t tmpfs tmpfs /ramdisk
# cp -R /somedir /ramdisk
the tmpfs will grow and shrink as necessary, so watch out
if you
put too much data on there and use up all your ram...
Another trick which might help speed up your existing disk
is
to mount the filesystem softdep,noatime, eg: from
/etc/fstab
/dev/wd0a / ffs rw,softdep,noatime 1 1
softdep will buffer writing updates back (this may or may
not be
a win - it can significantly reduce disk writes, but uses
more
ram... not always what you want on a low ram box)
noatime will stop the machine from updating the atime
(access time)
on files when they are read, which again reduces writes.
It will
still update the modification time when files are
written.
I'd suggest try noatime first to see, then try add softdep
later
to check if that helps more. Finally try the ramdisk...
(Though ramdisk + softdep is possibly going to consume all
your
ram 
Write a little script to help get consistent timing
numbers and
maybe even let us know how it goes
--
David/absolute -- www.NetBSD.org: No hype required
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