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From Tibor Gemes <tib...@gmail.com>
Subject Re: tinkering with limits while replicating
Date Tue, 05 Feb 2013 18:39:32 GMT
I've rewritten my filters into erlang and the continuous filtered
replications work faster with a few magnitude. T
2013.02.05. 19:23, "Nathan Vander Wilt" <nate-lists@calftrail.com> ezt írta:

> Hi Stephen,
>
> I've been doing some tests related to replication lately too
> (continuous+filtered in my case). I suspect the reason Futon hangs is
> because your whole VM is running out of RAM due to your very high
> os_process_limit. I went in to a bit more detail in
> http://mail-archives.apache.org/mod_mbox/couchdb-dev/201302.mbox/%3c70278F4A-FD08-4818-89B7-EA1B0AF846F5@gmail.com%3ebut
this setting basically determines the size of the couchjs worker pool —
> you'd probably rather have a bit of contention for the pool at a reasonable
> size (maybe ~100 per GB free, tops?) than start paging.
>
> hth,
> -natevw
>
>
>
> On Feb 4, 2013, at 5:15 PM, Stephen Bartell wrote:
>
> > Hi all,
> >
> > I'm hitting some limits while replicating , I'm hoping someone could
> advise.
> > Im running this in a VM on my macbook with the following allocated
> resources:
> > ubuntu 11.04
> > 4 cores @ 2.3ghz
> > 8 gb mem
> >
> > I'm doing a one-to-many replication.
> > 1) I create one db named test.
> > 2) Then create [test_0 .. test_99] databases.
> > 3) I then set up replications from test -> [test_0 .. test_99].  100
> replications total.
> > 4) I finally go to test and create a doc, hit save.
> >
> > When I hit save, futon becomes completely unresponsive for around 10sec.
>  It eventually returns to normal behavior.
> >
> > Tailing the couchdb log I find waves of the following errors:
> > [Tue, 05 Feb 2013 00:46:26 GMT] [info] [<0.6936.1>] Retrying POST
> request to http://admin:*****@localhost:5984/test_25/_revs_diff in 1.0
> seconds due to error {code,503}
> >
> > I see that the replicator is finding the server to be unresponsive.  The
> waves of these messages show that replicator retries in 0.25 sec, then 0.5
> sec, then 1sec, then 2sec.  This is expected.  Everything settles done
> after about 4 retries.
> >
> > So my first thought is resource limits.  I threw the book at it and set :
> > 1) max_dbs_open: 500
> > 2) os_process_limit: 5000
> > 3) http_connections: 20000
> > 4) ulimit -Sn 4096 (the hard limit is 4096)
> >
> > I really don't know whats reasonable for these values relative to how
> many replications I am setting up.  So these values, save max_dbs_open,
>  are all stabs in the dark.
> >
> > No change in performance.
> >
> > So, I'm at a loss now.  what can I do to get all this to work? Or what
> am I doing wrong?  And note that this is only a test.  I aim to quadruple
>  the amount of replications and have lots and lots of insertions on the so
> called "test" database.  Actually, there will be several of these
> one-to-many databases.
> >
> > I've heard people get systems up to thousands of dbs and replicators
> running just fine.  So I hope Im just not offering to right sacrifices up
> to couchdb yet.
> >
> > Thanks for any insight,
> >
> > sb
> >
>
>

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