Inline. J-D
On Tue, Jul 17, 2012 at 2:49 PM, Young Kim <[email protected]> wrote: > 1. There seems to be a dearth of articles in what hardware most people use > for their master servers. So, is there a recommended spec for the Master > servers? The HBase master in particular doesn't need anything special, it's your NameNodes you might want to make more reliable until you are using HA NN in 2.0 > 2. After some research, it seems that the normal for Region servers are lots > of RAM (24GB+), 12 spindle setups, and 2 x 6 cores. However, I recall reading > some articles warning against the allocation of more then 16GB to Regions. Is > this warning still valid, or do workarounds exist? It's a case of YMMV. We've been running with 25GB on our user-facing cluster for almost a year now and it never caused issues. We almost never run big inserts that put a lot of memory pressure (or any MR job that transit a lot of data in HBase, we have another cluster for that), so we never hit Full GCs. > 3. Finally, is there an article on the recommended heap allocation for each > processes? Mmm I guess there's a Cloudera article that talks about it, but generally you don't need to give more than 1GB (default) or 2 to the TaskTrackers, Datanodes and HMasters. Give everything you can to the Namenode. If you don't run MR jobs then give a lot of RAM to the region servers or split the memory between the tasks and the region servers. Hope this helps, J-D
