Re: [squid-users] Fluctuating LRU reference age

> Is there a known reason why the LRU reference age for an LRU cache
> directory sometimes jumps up and down between two levels that
> differ by several days? For example my cache recently filled-up to the
> low-water mark it immediately jumped from 180 to 185 days, and since
> then it's been switching up and down between 178 and 184. In the past
> I've seen larger jumps, such as as 30 to 50 days.
>
> The LRU policy implementation seems to be a queue with accessed
> objects sent to the tail and old objects deleted at the head. The
> displayed LRU reference age is taken from the "lastref" value of first
> unlocked object from the queue head.
>
> If everything is working as expected, the reference age should be able
> to drop instantaneously, but it shouldn't be able to rise faster than 1
> day per day.

 Hmm, reading that I get a feeling of the memory caching squid does coming
into play.
If I'm right its just old memory-only objects being shoved into the LRU
queue as they become disk objects.
Alternatively it could be objects becoming locked/unlocked for some reason.

Amos
Received on Thu Mar 06 2008 - 16:32:38 MST