[YLUG] RE: NTP losing sync (Stephen Patterson)

[David Morris]

Hello,

As well as the battery you could look at "interrupts". Some machines
don't do a good job of keeping the clock up to date when they are
dealing with large numbers of interrupts. To check this, run vmstat:

$ vmstat 5 6
procs -----------memory---------- ---swap-- -----io---- -system--
----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy
id wa
 0  0  33856 119716 123060 388496    0    0    23    21   69   94  2  1
97  0
 2  0  33856 119748 123072 388516    0    0     0    32  454 1516  0  1
98  0
 2  0  33856 119772 123072 388516    0    0     0     0  462 1535  5  3
... 

The "in" column (69, 454 and 462 on sample above. Always ignore 1st line
of vmstat) tells how many interrupts per second (Context Switches "cs"
column might also be high if interrupts are high.   High obviously
depends on the machine and what kind of workload it does, sometimes I
have seen a malfunctioning network card cause high levels of interrupts.
Other symptons are a "lumpy" response when typing at speed or when
taking characters from "chargen" tcp port 19.

Dave

On Mon, 2007-04-23 at 12:04 +0100, Andrew Scaife wrote:
> Just a thought, but if there's a battery on the motherboard of the
> server then I'd replace that and see if the problem persists.
> 
> Andrew
> 
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