Got it. Thanks for the help Erick. On Sat, Dec 5, 2015 at 1:02 PM, Erick Erickson <erickerick...@gmail.com> wrote:
> bq: Should zookeeper be installed along with solr on each box or should be > installed in separate 2 Virtual machines by itself? > > Zookeeper should be installed on an odd number of machines as it requires > a quorum which is (Number of zookeeper nodes)/2 + 1. With two ZKs, > if either of them fail you fall below quorum so you're actually _more_ > likely to fall below quorum than with one ZK. And more generally > more likely to fall below quorum with an even number of ZK nodes than > odd. > > But your question seems odd on another level. The number of Zookeepers you > run is entirely independent of the number of Solr nodes. You should just > pick a > number of Zookeepers and install them. Unless your installation is large, > 3 Zookeepers is usually enough. > > Whether they go on their own VMs or not isn't as interesting as > whether they should > go on separate physical boxes. That way if someone pulls a plug on a whole > physical server, then you still have a quorum, whereas if you put two ZKs > on a > single physical box you can lose quorum if that one machine goes down. > > Now, all that said, it's perfectly possible to run with just a > _single_ zookeeper > running on a single box that's may or may not be running Solr. The risk is > that > your cluster will be unable to index documents (but still maybe able to > search) > if that ZK becomes unavailable for any reason. I run this way all the time > for > development. > > In a small installation where all your servers are physically located > together and you run with a single ZK node, if that ZK node regularly > becomes > unavailable, you have problems that adding more ZK nodes probably won't > help > with ;) > > Best, > Erick > > On Sat, Dec 5, 2015 at 4:09 AM, Gaurav Patel <gaura...@gmail.com> wrote: > > Thanks Toke. Your input has been informative and valuable. > > I will go through the links you provided and will let you know what we > end > > up going. > > > > On Sat, Dec 5, 2015 at 5:02 AM, Toke Eskildsen <t...@statsbiblioteket.dk> > > wrote: > > > >> Gaurav Patel <gaura...@gmail.com> wrote: > >> > 3 Physical Machines with 60 cpu cores and 512 GB RAM each. > >> > EMC Isilon Appliance with PB storage. It can be accessed via HDFS or > NFS. > >> > >> We have experimented a little bit with smaller machines, backed by EMC > >> Isilon over NFS. That worked surprisingly well, but ultimately did not > >> scale for us as we could not justify paying for enterprise SSDs for the > >> Isilon. There is a write-up at > >> https://sbdevel.wordpress.com/2013/12/06/danish-webscale/ > >> > >> > Can we use solr cloud for this setup? > >> > >> Yes. That is independent of the backing storage. > >> > >> > How many instances of SOLR are recommended per physical machines > >> > and how much ram should be allocated to it. > >> > >> "That depends". > >> > >> > http://lucidworks.com/blog/2012/07/23/sizing-hardware-in-the-abstract-why-we-dont-have-a-definitive-answer/ > >> > >> The amount of RAM for JVMs should be whatever is needed. Or to put it > >> another way: There are some explicitly configured internal caches in > Solr, > >> but just setting Xmx to a very high number will not help performance. On > >> the contrary, it will lead to long garbage collecting pauses and eat > from > >> the precious disk cache. > >> > >> There are some rules of thumb for running Solr, but my own meta rule of > >> thumbs is that their applicability goes down when scale goes up. One of > the > >> rules of thumb is to have 1 Solr instance per machine. But running JVMs > >> with very large heaps (100GB+) has the potential of extremely long > garbage > >> collection pauses and also implies a larger memory overhead due to > internal > >> pointer size. > >> > >> > Should zookeeper be installed along with solr on each box or should be > >> > installed in separate 2 Virtual machines by itself? > >> > >> I have no opinion on that. > >> > >> > Can we run kakfa and cassandra along with solr on each physical > machine? > >> > >> Sure, but they will of course compete with Solr for resources. > >> > >> > Anybody running Solr with HDFS in production? > >> > >> It is a recurring theme on this mailing list at least. It can be > searched > >> at > >> https://www.mail-archive.com/solr-user@lucene.apache.org/ > >> > >> - Toke Eskildsen > >> >
