On Wed, Sep 5, 2012 at 6:25 AM, Eric Czech <[email protected]> wrote: > Hi everyone, > > Does anyone have any recommendations on how to maintain low latency for > small, individual reads from HBase while MapReduce jobs are being run? Is > replication a good way to handle this (i.e. run small, low-latency queries > against a replicated copy of the data and run the MapReduce jobs on the > master copy)?
MapReduce is blowing your caches or higher i/o is sending up latency when you have cache miss? Or its using all the CPU? Dependent on how its impinges, you could trying corralling mapreduce (cgroups/jail) or go to an extreme and keep a low latency OLTP cluster running well-known, well-behaved mapreduce jobs replicating into a batch cluster where mapreduce is allowed free rein (This is what we do where I work. We also cgroup mapreduce cluster even on our batch cluster so random big MR doesn't make the pagers go off during sleepy time). St.Ack
