Red Hat Bugzilla – Bug 193696
Not using all available system memory - swapping too aggressive - high load average (iowait)
Last modified: 2007-11-30 17:07:25 EST
Description of problem:
System swaps too aggressively and only utilises +-30% of available system
memory (reading discussion threads indicates that this only shows up when
the system has more than 1GB of RAM).
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. AMD Athlon 64 3000+ Processor
2. nVidia nForce4 chipset (ASUS A8N5X Motherboard)
3. 1GB of RAM
put load on the server and available system memory is +-750KB. Swap
utilisation increases and processes increase slowing the system due to
high iowait (aggressive memory swapping)
Should only start swapping once system memory starts getting low, no?
System was previously running RHEL3.7 without problems, MRTG display of
available system memory shows the problem quite clearly (attached).
RedHat do have a document called 'Understanding Virtual Memory In Red Hat
Enterprise Linux 4' but I simply don't understand what I should be changing:
Created attachment 130298 [details]
MRTG graph of available system memory show system not using everything before starting to aggressively swap
hmmm...this looks a lot like bz #188141. Can you please try the U4 beat kernel
and let me know if this fixes it for you. The kernel is 2.6.9-37.
Found additional information from other people experiencing the same issue
in CentOS 4:
Bug ID: 0001174
Summary: Extremely high load average and 100% CPU utilization
Yes, i'm aware of this. I'm pretty sure the U4 beta kernel mention =ed in
comment #2 will resolve this issue. Also, just to be clear no VM tuning should
The kernel-2.6.9-37.EL perfectly resolves the problem we were experiencing.
Many thanks for your prompt assistance!
glad to hear that :)
*** This bug has been marked as a duplicate of 188141 ***