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/%[email protected]%3e but 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 >
