Hi,

to help us to diagnose this problem, this is our stats :

Memory usage (server) :
free : 11.7 GB
used : 3.98 GB

Memcached bytes used :
used 1.23 G (constant now)
max available : 1.9 G

memcached current connections :
52

memcached hits and misses :
hits/sec : 14
misses/sec : 2

memcached items :
items cached : 94814 (constant now)

memcached requests/s :
get/s : 16
set/s : 0

memcached network traffic :
output : 4 k
input : 1109


If memcached allocate by page 1MB, considering that we have 100.000
memcached items, it corresponds to 100 GB memory (impossible).
Thanks for your help !

On 14 mai, 23:12, Colin Pitrat <[email protected]> wrote:
> In fact, with default settings, memcached allocate by page of ~1 MB
> (exact page size is the nearest multiple of chunk size). Each time a
> page is full (i.e. no free chunk), if allocated memory does not reach
> the memory limit, another page is allocated for this chunk size.
>
> So if you allocate a lot of small chunks for small items, and they are
> evicted, the memory cannot be reused for bigger chunks. The only
> solution is to restart memcached, a flush will not help.
>
> There is a mode that always allocate 1MB pages, which allows to
> reallocate a page to another chunk size. However, I'm not sure that it
> is the problem here. Having output of stats and stats slabs will help
> to diagnose.
>
> 2009/5/14 luciano11 <[email protected]>:
>
>
>
> > My understanding of the current software is that an individual memory
> > bucket will grow in size as needed as long as there is free memory,
> > but that growth of one memory bucket cannot cause another bucket to
> > evict data.
>
> > So is it possible that the cache is partially filled by another memory
> > bucket that has data with no expiration?
>
> > On May 14, 9:38 am, Dustin <[email protected]> wrote:
> >> On May 14, 2:37 am, TopLess <[email protected]> wrote:
>
> >> > Hi Colin,
>
> >> > thx for your answer.
> >> > This is our configuration :
> >> > # memory
> >> > -m 10000
>
> >> > In fact, each server had 16 GB and only 3 GB is reserved by system, so
> >> > there is no problem concerning the free memory.
> >> > So we don't reach max memory usage, but memcached items stays strictly
> >> > constant.
> >> > An idea ?
>
> >>   That does seem odd.  The output of "stats" and "stats items" and
> >> "stats slabs" would help.
>
> >>   What expiration are you setting for these items?  What version of
> >> memcached (stats will include that).

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