Hey Peter, Thanks for your reply. My question was mainly about the fact there seems to be two different aspects to the solr RAM usage: in-process and out-process. By that I mean, yes i know the many different parameters/caches to do with solr in-process memory usage and related culprits, however I also understand that as for actual index access (posting list, positional index etc), solr mostly delegates the access/caching of this to the OS/disk cache. So I guess my question is more about that: namely, what would be a good way to calculate an overall ram requirement profile for a server running solr? Also, I was under the impression benefits from RAMDirectory would be minimal when disk caches are effective no? And does RAMDirectory work with replication? if so, doesnt it slow it down? ( on each replication, load up entire index to RAM at once? )
Peter Sturge wrote: > > On Tue, Mar 16, 2010 at 9:08 PM, KaktuChakarabati > <jimmoe...@gmail.com>wrote: > >> >> Hey, >> I am trying to understand what kind of calculation I should do in order >> to >> come up with reasonable RAM size for a given solr machine. >> >> Suppose the index size is at 16GB. >> The Max heap allocated to JVM is about 12GB. >> >> The machine I'm trying now has 24GB. >> When the machine is running for a while serving production, I can see in >> top >> that the resident memory taken by the jvm is indeed at 12gb. >> Now, on top of this i should assume that if i want the whole index to fit >> in >> disk cache i need about 12gb+16gb = 28GB of RAM just for that. Is this >> kind >> of calculation correct or am i off here? >> >> > Hmmm..not quite. The idea of the ram usage isn't to simply hold the index > in > memory - if you want this use a RAMDirectory. > The memory being used will be a combination of various caches (Lucene and > Solr), index buffers et al., and of course the server itself. The > specifics > depend very > much on what your server is doing at any given time - e.g. lots of > concurrent searches, lots of indexing, both etc., and how things are setup > in your solrconfig.xml. > > A really excellent resource that's worth looking at regarding all this can > be found here: > > http://www.lucidimagination.com/Community/Hear-from-the-Experts/Articles/Scaling-Lucene-and-Solr > > > >> Any other recommendations Anyone could make w.r.t these numbers ? >> >> Thanks, >> -Chak >> -- >> View this message in context: >> http://old.nabble.com/Solr-RAM-Requirements-tp27924551p27924551.html >> Sent from the Solr - User mailing list archive at Nabble.com. >> >> > > -- View this message in context: http://old.nabble.com/Solr-RAM-Requirements-tp27924551p27926536.html Sent from the Solr - User mailing list archive at Nabble.com.
