experiences beyond 4 GB RAM with 2.4.22

From: Stephan von Krawczynski
Date: Tue Sep 09 2003 - 04:02:42 EST


Hello,

lately I upgraded my testbox from 2 to 6 GB ram and found out some oddities I
would like to hear your opinions.
The box ran flawlessly and performant with 2 GB - was in fact a real joy.
After upgrading the ram and recompiling kernel 2.4.22 with support for 64 GB I
noticed:

1) nfs clients see timeouts again, like

Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 not responding, still
trying
Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 OK
Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 not responding, still
trying
Sep 9 03:37:35 clienta kernel: nfs: server 192.168.1.1 OK
Sep 9 03:41:13 clienta kernel: nfs: server 192.168.1.1 not responding, still
trying
Sep 9 03:41:13 clienta kernel: nfs: server 192.168.1.1 OK

Both are 2.4.22. 192.168.1.1 is the testbox. I saw those with 2GB, but could
fix it through more nfs-daemons and

echo 2097152 >/proc/sys/net/core/rmem_max
echo 2097152 >/proc/sys/net/core/wmem_max

Are these values too small for 6 GB?

2) Box is very slow, kswapd looks very active during tar of a local harddisk.
Interactivity is really bad. Seems vm has a high time looking for free or
usable pages. Compared to 2 GB the behaviour is unbelievably bad.

3) Network performance has a remarkable dropdown during above tar. In fact
doing simple pings every few minutes shows that quite a lot of them are simply
dropped, never make it over the ethernet.

I am really astonished about this. Can some kind soul give me hints or maybe
patches to try?

Regards,
Stephan
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