Invalid memory stats from vmstat and sysctl vm.vmtotal?

[RW]

On Wed, 30 Nov 2011 12:39:10 -0000
Steven Hartland wrote:

> We're seeing some impossible memory usage stats reported on machines
> here from vmstat and sysctl vm.vmtotal.
> 
> We have machines reporting to be using 31GB total when they only have
> 8GB physical and are not using any swap.
> 
> Here's an output from one of our machines:-
> vmstat -c 2 -w 1 -n 0 
>  procs      memory      page                      faults         cpu
>  r b w     avm    fre   flt  re  pi  po    fr  sr   in   sy   cs us
> sy id 0 0 0  31768M  2112M   586   0   0   0   421   0  106  270
> 569  0  6 94 0 0 0  31768M  2112M     2   0   0   0     0   0  370
> 8139 3996  0  1 99
> 
> ...
> It looks like it may be out by a factor of 4, possibly due to the fact
> the its a 4k page size not 1k as indicated by the vmstat man page:-
> 

I don't think so, I have 16GB and tops shows:

Mem: 817M Active, 396M Inact, 1364M Wired, 82M Cache, 1282M Buf, 13G
Free

but  

vmstat -c 2 -w 1 -n 0 
 procs      memory      page                      faults         cpu
 r b w     avm    fre   flt  re  pi  po    fr  sr   in   sy   cs us sy
id 0 0 0   9750M    13G   450   5   3   1   560   0  234 50201 5206  2
2 96 1 0 0   9742M    13G    79   4   0   0   573   0  239 51886 4700
0  1 99