Henrik,
AIX also reports i/o wait in its vmstat output in column 16 under wa of cpu
which it would be nice to have in the graphs.
kthr memory page faults cpu
----- ----------- ------------------------ ------------ -----------
r b avm fre re pi po fr sr cy in sy cs us sy id wa
0 2 238300 239351 0 0 0 60 108 0 110 79 83 8 30 30 32
0 2 238803 238827 0 0 0 0 0 0 498 3066 334 1 2 97 1
Chris
-----Original Message-----
From: Henrik Stoerner [SMTP:user-ce4a2c883f75@xymon.invalid]
Sent: Tuesday, January 25, 2005 5:04 PM
To: user-ae9b8668bcde@xymon.invalid
Subject: Re: [hobbit] vmstat graphing with CPU io wait
On Tue, Jan 25, 2005 at 08:27:37AM -0500, Tom Georgoulias wrote:
Henrik Storner wrote:
Where do you get the I/O wait information from ?
On RHEL3 (procps-2.0.17-10), there is a value for it in column 14 of
vmstat's output, labeled "wa" under "cpu"
Aha! So that's it - I had been wondering a bit why my load graphs
didn't always add up to 100% !
This is quite interesting, and definitely something that should be
tracked. So I hope you don't mind that I've tried adding it myself ...
One annoying bit with the RRD files is that changing the dataset
(e.g. adding an extra variable) is not possible. So adding the
cpu_wait data will break any existing vmstat data that has been
collected. So if we're gonna break the vmstat RRD layout for Linux
clients, we might as well do it now before the official release. And
that should also include getting the very old layout (the one from
Linux 2.2 kernels, with the "r b w" proces-counts) aligned with the
new layout - effectively creating a single vmstat RRD format
regardless of what Linux version you are running.
So: I've modified the Linux vmstat RRD layout to always include the
"cpu_w" (from the very old vmstat version) and "cpu_wait" columns
(from the latest vmstat versions). If the client doesn't report a
value for these, they are set to the special RRD-value "undefined". So
when someone upgrades a system from Linux 2.2. to 2.4, or from 2.4 to
2.6, the vmstat data will still work.
I've also defined a "vmstat1" graph similar to the normal "vmstat"
graph, but with the cpu_wait data added (it stacks on top of the
"system" time, below "user" time).
Some sample graphs (they don't have any data yet, so you're probably
better off waiting a couple of hours before you view them):
Linux 2.6 host:
http://www.hswn.dk/hobbit-cgi/hobbitgraph.sh?host=voodoo.hswn.dk&service=v
mstat1&graph=hourly
Linux 2.4 host:
http://www.hswn.dk/hobbit-cgi/hobbitgraph.sh?host=tyge.sslug.dk&service=vm
stat1&graph=hourly
Linux 2.2 host (actually 2.4, but an old vmstat version):
http://www.hswn.dk/hobbit-cgi/hobbitgraph.sh?host=fenris.hswn.dk&service=v
mstat1&graph=hourly
Henrik
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