I am architecting a solution for moving a large number of documents out of our MySQL database to C*. We use Solr to index these documents. I’ve recently become aware of a few different packages that integrate C* and Solr. At first blush, this seems like the perfect fit, as it would eliminate a complicated and somewhat fragile system that manages the indexing of our documents. However, I have a significant concern that would certainly be a show-stopper, unless I’m mistaken about some assumptions I’ve made. If any of you can confirm that my concern is justified, or let me know where I’m wrong, I’d greatly appreciate it.
So here’s what I think will be an issue. The guiding principle in setting up our current Solr cluster (which was done before my time), is that the index has to fit in the heap. Each node in our current Solr cluster has 32 GB of RAM and runs with a 28 GB heap, and serves up less than 28 GB of index. When I think about combining Solr and C*, it would seem that I’d need to cough up 8 GB for C*, leaving 20 GB for Solr. The entire Solr index and the entire MySQL database are roughly the same size. If I assume that the data will consume roughly the same space on C* as it does on MySQL, then each C* would be limited to roughly the same amount of data as the Solr index, or about 20 GB. If I have a replication factor of 3, then I need a node for each 7 GB of data. That is obviously a problem. We have about 1 TB of data. It would take about 150 nodes. Is C*/Solr integration only feasible for applications for which a small subset of the data is indexed in Solr, or am I mistaken about the requirement that the Solr index be able to fit in heap? Thanks in advance Robert
