Hey everyone. Been doing some load testing over the past few days. I've been throwing a good bit of load at an instance of solr and have been measuring response time. We're running a variety of different keyword searches to keep solr's cache on its toes.
I'm running two exact same load testing scenarios: one with indexes residing in /dev/shm and another from local disk. The indexes are about 4.5GB in size. On both tests the response times are the same. I wasn't expecting that. I do see the java heap size grow when indexes are served from disk (which is expected). When the indexes are served out of /dev/shm, the java heap stays small. So in general is this consistent behavior? I don't really see the advantage of serving indexes from /dev/shm. When the indexes are being served out of ramdisk, is the linux kernel or the memory mapper doing something tricky behind the scenes to use ramdisk in lieu of the java heap? For what it is worth, we are running x_64 rh5.4 on a 12 core 2.27Ghz Xeon system with 48GB ram. Thoughts? -Park
