Check for thrashing

Davy Durham pubaddr2 at davyandbeth.com
Wed Oct 5 07:16:14 CEST 2005


Timothy O'Hare wrote:

> You could monitor the CPU load and swap space usage?
>
Yeah, but my question was what values from vmstat would mean that it's 
thrashing.. a plugin would seem simple to write to check that

> Guy B. Purcell wrote:
>
>>
>> On Oct 4, 2005, at 19:26, Davy Durham wrote:
>>
>>>  Does anyone know of a plugin that can check if a machine is  
>>> "thrashing" by which I mean it continues to swap and swap.. because  
>>> either there is too little ram, or too many processes running on  
>>> the box.
>>
>>
>>
>> I think such a thing would be unnecessary, really:  if a box is  
>> thrashing (in the canonical sense of that word--something happens  
>> that causes it to have to work harder, which slows everything down 
>> so  jobs pile up, causing it to have to work even harder, and so on 
>> in a  catch-22 cycle), then the various services on it you're 
>> otherwise  monitoring will time out because there aren't enough 
>> resources of one  kind or another to handle the monitor requests.
>>
>>>   I would think a vmstat command could tell you that, though it  
>>> would need a few seconds to determine.  And I'm not sure what  
>>> numbers would indicate what a bad amount would be.
>>
>>
>>
>> The actual implementation of such a thing would need to be carefully  
>> crafted to work across multiple OSes.  IMHO, it's not worth the  
>> effort:  if a box truly is thrashing, you should know all about it  
>> from existing monitors.
>>
>> -Guy
>>
>>
>>
>>
>> -------------------------------------------------------
>> This SF.Net email is sponsored by:
>> Power Architecture Resource Center: Free content, downloads, 
>> discussions,
>> and more. http://solutions.newsforge.com/ibmarch.tmpl
>> _______________________________________________
>> Nagios-users mailing list
>> Nagios-users at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/nagios-users
>> ::: Please include Nagios version, plugin version (-v) and OS when 
>> reporting any issue. ::: Messages without supporting info will risk 
>> being sent to /dev/null
>
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by:
> Power Architecture Resource Center: Free content, downloads, discussions,
> and more. http://solutions.newsforge.com/ibmarch.tmpl
> _______________________________________________
> Nagios-users mailing list
> Nagios-users at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/nagios-users
> ::: Please include Nagios version, plugin version (-v) and OS when 
> reporting any issue. ::: Messages without supporting info will risk 
> being sent to /dev/null




-------------------------------------------------------
This SF.Net email is sponsored by:
Power Architecture Resource Center: Free content, downloads, discussions,
and more. http://solutions.newsforge.com/ibmarch.tmpl
_______________________________________________
Nagios-users mailing list
Nagios-users at lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nagios-users
::: Please include Nagios version, plugin version (-v) and OS when reporting any issue. 
::: Messages without supporting info will risk being sent to /dev/null





More information about the Users mailing list