As far as the second option goes, unless you are using a large amount of memory and you reach a point where a JVM can't sensibly deal with a GC load, having multiple JVMs wouldn't buy you much. With a 26GB index, you probably haven't reached that point. There are also other shared resources at an instance level like connection pools and ZK connections, but those are tunable and you probably aren't pushing them as well (I would imagine you are just trying to have only a handful of shards given that you aren't sharded at all currently).
That leaves single vs multiple machines. Assuming the network isn't a bottleneck, and given the same amount of resources overall (number of cores, amount of memory, IO bandwidth times number of machines), it shouldn't matter between the two. If you are procuring new hardware, I would say buy more, smaller machines, but if you already have the hardware, you could serve as much as possible off a machine before moving to a second. There's nothing which limits the number of shards as long as the underlying machine has the sufficient amount of parallelism. Again, this advice is for a small number of shards, if you had a lot more (hundreds) of shards and significant volume of requests, things start to become a bit more fuzzy with other limits kicking in. On 28 Oct 2014 09:26, "Anca Kopetz" <anca.kop...@kelkoo.com> wrote: > Hi, > > We have a SolrCloud configuration of 10 servers, no sharding, 20 > millions of documents, the index has 26 GB. > As the number of documents has increased recently, the performance of > the cluster decreased. > > We thought of sharding the index, in order to measure the latency. What > is the best approach ? > - to use shard splitting and have several sub-shards on the same server > and in the same tomcat instance > - having several shards on the same server but on different tomcat > instances > - having one shard on each server (for example 2 shards / 5 replicas on > 10 servers) > > What's the impact of these 3 configuration on performance ? > > Thanks, > Anca > > -- > > Kelkoo SAS > Société par Actions Simplifiée > Au capital de € 4.168.964,30 > Siège social : 8, rue du Sentier 75002 Paris > 425 093 069 RCS Paris > > Ce message et les pièces jointes sont confidentiels et établis à > l'attention exclusive de leurs destinataires. Si vous n'êtes pas le > destinataire de ce message, merci de le détruire et d'en avertir > l'expéditeur. >
