Thanks, I see Patrick has replied in the archives but I don't have it in my mail (yet). I'd probably use 2 EC2 High-mem instances (17GB/instance), and I have no watches at all, so I should be able to store between 5-10M data, but I'll test that over the summer. I'll post the results here (and will publish my simple sync, no-watch Scala client as well).
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Best, Maarten Op 15 jul 2010, om 17:57 heeft Benjamin Reed het volgende geschreven: > i think there is a wiki page on this, but for the short answer: > > the number of znodes impact two things: memory footprint and recovery time. > there is a base overhead to znodes to store its path, pointers to the data, > pointers to the acl, etc. i believe that is around 100 bytes. you cant just > divide your memory by 100+1K (for data) though, because the GC needs to be > able to run and collect things and maintain a free space. if you use 3/4 of > your available memory, that would mean with 4G you can store about three > million znodes. when there is a crash and you recover, servers may need to > read this data back off the disk or over the network. that means it will take > about a minute to read 3G from the disk and perhaps a bit more to read it > over the network, so you will need to adjust your initLimit accordingly. > > of course this is all back-of-the-envelope. i would suggest doing some quick > benchmarks to test and make sure your results are in line with expectation. > > ben > > On 07/15/2010 02:56 AM, Maarten Koopmans wrote: >> Hi, >> >> I am mapping a filesystem to ZooKeeper, and use it for locking and mapping a >> filesystem namespace to a flat data object space (like S3). So assuming >> proper nesting and small ZooKeeper nodes (< 1KB), how many nodes could a >> cluster with a few GBs of memory per instance realistically hold totally? >> >> Thanks, Maarten > >