I'm using all defaults created with ceph-deploy

I will try the rgw cache setting.  Do you have any other recommendations?


On Thu, Sep 5, 2013 at 1:14 PM, Yehuda Sadeh <[email protected]> wrote:

> On Thu, Sep 5, 2013 at 9:49 AM, Sage Weil <[email protected]> wrote:
> > On Thu, 5 Sep 2013, Bill Omer wrote:
> >> Thats correct.  We created 65k buckets, using two hex characters as the
> >> naming convention, then stored the files in each container based on
> their
> >> first two characters in the file name.  The end result was 20-50 files
> per
> >> bucket.  Once all of the buckets were created and files were being
> loaded,
> >> we still observed an increase in latency overtime.
> >
> > This might be going too far in the opposite direction.  I would target
> > 1000's of objects per bucket, not 10's.  The radosgw has to validate
> > bucket ACLs on requests.  It caches them, but it probably can't cache 64K
> > of them (not by default at least!).  And even if it can, it will take a
> > long long time for the cache to warm up.  In any case, the end result is
> > that there is probably an extra rados request going on on the backend for
> > every request.
> >
> > Maybe try over ~1000 buckets and see how that goes?  And give the cache a
> > bit of time to warm up?
>
>
> There's actually a configurable that can be played with. Try setting
> something like this in your ceph.conf:
>
> rgw cache lru size = 100000
>
> That is 10 times the default 10k.
>
>
> Also, I don't remember if the obvious has been stated, but how many
> pgs do you have on your data and index pools?
>
> Yehuda
>
> >
> > sage
> >
> >
> >
> >> Is there a way to disable indexing?  Or are there other settings you can
> >> suggest to attempt to speed this process up?
> >>
> >>
> >> On Wed, Sep 4, 2013 at 5:21 PM, Mark Nelson <[email protected]>
> wrote:
> >>       Just for clarification, distributing objects over lots of
> >>       buckets isn't helping improve small object performance?
> >>
> >>       The degradation over time is similar to something I've seen in
> >>       the past, with higher numbers of seeks on the underlying OSD
> >>       device over time.  Is it always (temporarily) resolved writing
> >>       to a new empty bucket?
> >>
> >>       Mark
> >>
> >>       On 09/04/2013 02:45 PM, Bill Omer wrote:
> >>       We've actually done the same thing, creating 65k buckets
> >>       and storing
> >>       20-50 objects in each.  No change really, not noticeable
> >>       anyway
> >>
> >>
> >>       On Wed, Sep 4, 2013 at 2:43 PM, Bryan Stillwell
> >> <[email protected] <mailto:[email protected]>>
> >> wrote:
> >>
> >>     So far I haven't seen much of a change.  It's still working
> >> through
> >>     removing the bucket that reached 1.5 million objects though
> >> (my
> >>     guess is that'll take a few more days), so I believe that
> >> might have
> >>     something to do with it.
> >>
> >>     Bryan
> >>
> >>
> >>     On Wed, Sep 4, 2013 at 12:14 PM, Mark Nelson
> >>     <[email protected] <mailto:[email protected]>>
> >> wrote:
> >>
> >>         Bryan,
> >>
> >>         Good explanation.  How's performance now that you've
> >> spread the
> >>         load over multiple buckets?
> >>
> >>         Mark
> >>
> >>         On 09/04/2013 12:39 PM, Bryan Stillwell wrote:
> >>
> >>             Bill,
> >>
> >>             I've run into a similar issue with objects averaging
> >>             ~100KiB.  The
> >>             explanation I received on IRC is that there are
> >> scaling
> >>             issues if you're
> >>             uploading them all to the same bucket because the
> >> index
> >>             isn't sharded.
> >>                The recommended solution is to spread the objects
> >> out to
> >>             a lot of
> >>             buckets.  However, that ran me into another issue
> >> once I hit
> >>             1000
> >>             buckets which is a per user limit.  I switched the
> >> limit to
> >>             be unlimited
> >>             with this command:
> >>
> >>             radosgw-admin user modify --uid=your_username
> >> --max-buckets=0
> >>
> >>             Bryan
> >>
> >>
> >>             On Wed, Sep 4, 2013 at 11:27 AM, Bill Omer
> >>             <[email protected] <mailto:[email protected]>
> >>             <mailto:[email protected]
> >> <mailto:[email protected]>>>
> >>             wrote:
> >>
> >>                  I'm testing ceph for storing a very large
> >> number of
> >>             small files.
> >>                    I'm seeing some performance issues and would
> >> like to
> >>             see if anyone
> >>                  could offer any insight as to what I could do
> >> to
> >>             correct this.
> >>
> >>                  Some numbers:
> >>
> >>                  Uploaded 184111 files, with an average file
> >> size of
> >>             5KB, using
> >>                  10 separate servers to upload the request using
> >> Python
> >>             and the
> >>                  cloudfiles module.  I stopped uploading after
> >> 53
> >>             minutes, which
> >>                  seems to average 5.7 files per second per node.
> >>
> >>
> >>                  My storage cluster consists of 21 OSD's across
> >> 7
> >>             servers, with their
> >>                  journals written to SSD drives.  I've done a
> >> default
> >>             installation,
> >>                  using ceph-deploy with the dumpling release.
> >>
> >>                  I'm using statsd to monitor the performance,
> >> and what's
> >>             interesting
> >>                  is when I start with an empty bucket,
> >> performance is
> >>             amazing, with
> >>                  average response times of 20-50ms.  However as
> >> time
> >>             goes on, the
> >>                  response times go in to the hundreds, and the
> >> average
> >>             number of
> >>                  uploads per second drops.
> >>
> >>                  I've installed radosgw on all 7 ceph servers.
> >>  I've
> >>             tested using a
> >>                  load balancer to distribute the api calls, as
> >> well as
> >>             pointing the
> >>                  10 worker servers to a single instance.  I've
> >> not seen
> >>             a real
> >>                  different in performance with this either.
> >>
> >>
> >>                  Each of the ceph servers are 16 core Xeon
> >> 2.53GHz with
> >>             72GB of ram,
> >>                  OCZ Vertex4 SSD drives for the journals and
> >> Seagate
> >>             Barracuda ES2
> >>                  drives for storage.
> >>
> >>
> >>                  Any help would be greatly appreciated.
> >>
> >>
> >>
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> >>
> >>
> >>
> >>
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> >>
> >>             *Bryan Stillwell*
> >>             SENIOR SYSTEM ADMINISTRATOR
> >>
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> >>
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> >>
> >>     --
> >>     Photobucket <http://photobucket.com>
> >>
> >>     *Bryan Stillwell*
> >>
> >>     SENIOR SYSTEM ADMINISTRATOR
> >>
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> >> <mailto:[email protected]>
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> >>
> >>
> >>
> >>
> >
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