[hobbit] vmstat graphing with CPU io wait

[Morris, Chris (Shared Services)]

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:henrik at hswn.dk]
> Sent:	Tuesday, January 25, 2005 5:04 PM
> To:	hobbit at hswn.dk
> 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
> 
> To unsubscribe from the hobbit list, send an e-mail to
> hobbit-unsubscribe at hswn.dk
> 


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