Swapfile over NFS

I made a diskless workstation out of a laptop. It has 768M of RAM. I'm
trying to make a swap file. I did:

dd if=/dev/zero of=/swapfile bs=1M count=10
mkswap /swapfile
# returned "Setting up swapspace version 1, size = 10236 KiB"
# I guess it uses 4 KB for accounting
swapon /swapfile
# returned "rw_swap_page: bad swap file
# Unable to find swap-space signature
# swapon: /swapfile: Invalid argument"

This same file works from the host, running the same distribution and
kernel. Is there something special I have to do since it's over NFS? Or
is 768M enough that I don't need swap?

--
-eben (E-Mail Removed)m home.tampabay.rr.com/hactar

rm -f /bin/laden

Andrey Asadchev <(E-Mail Removed)> wrote:

> I dont believe you can do swap over NFS. It might have changed in
> recent version of kernel, but i doubt it. There are couple of good
> reason why you should not do it. IMO the main one is it is not
> reliable enough.

You can, but you need a patch. The Linux Terminal Server Project has it
in their kernel, so there would be a good place to start.

Although I agree with what Andrey said, you probably don't need it.

--
Cameron Kerr
(E-Mail Removed) : http://nzgeeks.org/cameron/
Empowered by Perl!

Hactar wrote:
> I made a diskless workstation out of a laptop. It has 768M of RAM. I'm
> trying to make a swap file. I did:
>
> dd if=/dev/zero of=/swapfile bs=1M count=10
> mkswap /swapfile
> # returned "Setting up swapspace version 1, size = 10236 KiB"
> # I guess it uses 4 KB for accounting
> swapon /swapfile
> # returned "rw_swap_page: bad swap file
> # Unable to find swap-space signature
> # swapon: /swapfile: Invalid argument"
>
> This same file works from the host, running the same distribution and
> kernel. Is there something special I have to do since it's over NFS? Or
> is 768M enough that I don't need swap?
>

768M is a lot of memory IMHO. You should not need swap for running X11
+ Gnome + Mozilla + etc. Only very memory intensive programs can eat up
that much memory. For comparison - i have about 500 Mb total (swap+ram)
and i never ran out of memory yet.

I dont believe you can do swap over NFS. It might have changed in
recent version of kernel, but i doubt it. There are couple of good
reason why you should not do it. IMO the main one is it is not
reliable enough.

I run diskless cluster with nodes having between 128 and 198 MB without
swap files. I have made few diskless X machines - they had about 64MB.
No problems related to memory running low on any of them.

In article <(E-Mail Removed)>,
Cameron Kerr <(E-Mail Removed)> wrote:
> Andrey Asadchev <(E-Mail Removed)> wrote:
>
> > I dont believe you can do swap over NFS. It might have changed in
> > recent version of kernel, but i doubt it. There are couple of good
> > reason why you should not do it. IMO the main one is it is not
> > reliable enough.

It would be slow, if it worked.

> You can, but you need a patch. The Linux Terminal Server Project has it
> in their kernel, so there would be a good place to start.
>
> Although I agree with what Andrey said, you probably don't need it.

I won't be doing anything memory-intensive on this machine, and since Linux
gets along fine without swap, I won't bust my butt (or patch my kernel)
trying to get it.

--
-eben (E-Mail Removed)m home.tampabay.rr.com/hactar

Two atoms are walking along. Suddenly, one stops. The other says,
"What's wrong?" "I've lost an electron." "Are you sure?" "I'm positive!"