So our cell sizes will be 350kb on average with 5-10 terabytes per server, I just want to keep the count of Regions under 1000, per server
-Jack On Sep 22, 2010, at 2:44 AM, Ryan Rawson <[email protected]> wrote: > Region size is one of those tricky things, there are a few factors to > consider: > > - regions are the basic element of availability and distribution. > - HBase scales by having regions across many servers. Thus if you > have 2 regions for 16GB data, on a 20 node machine you are a net loss > there. > - High region count has been known to make things slow, this is > getting better, but it is probably better to have 700 regions than > 3000 for the same amount of data. > - Low region count prevents parallel scalability as per point #2. > This really cant be stressed enough, since a common problem is loading > 200MB data into HBase then wondering why your awesome 10 node cluster > is mostly idle. > - There is not much memory footprint difference between 1 region and > 10 in terms of indexes, etc, held by the regionserver. > > Generally speaking I stick to the default, go smaller for hot tables, > or manually split them, and go with a 1GB region size on our largest > 900 GB table. > > -ryan > > On Wed, Sep 22, 2010 at 12:01 AM, Jack Levin <[email protected]> wrote: >> Yes, I am thinking to put 10 to 15 million files on each regionserver >> (well, not literally, but be controlled by regionserver). So thats >> close to 4 TB worth of regions, which is about 4GB per region should >> we target 1000 regions per server. Note, not all files are 'hot', and >> I only expect to keep about 1% super hot, and 5% relatively hot, the >> rest are cold. So in terms of keeping hbase blocks in RAM, that >> should be adequate, for the rest we can afford a trip into hdfs. >> >> If servers are running 8 GB of ram, and are shared for regionservers >> and datanodes, how much heap should I allocate to each? 6GB for RS >> and 1GB for DN? >> >> Also, on the question whether 8 core x 16G Ram helps a Master server >> to bring up the cluster faster, the answer is definitely - yes. It >> took only 90 seconds to load 5000 regions across 13 servers, where >> same task for Dual Core 8G Ram, took nearly 10 minutes. >> >> -Jack >> >> >> >> On Tue, Sep 21, 2010 at 11:38 PM, Stack <[email protected]> wrote: >>> On Tue, Sep 21, 2010 at 11:11 PM, Jack Levin <[email protected]> wrote: >>>> Its definitely binary, and I can even load it in my browser but >>>> setting appropriate headers. So I guess for PUT and GET via Accept: >>>> application/octet-stream there is no base64 encoding at all. >>>> >>> >>> OK. Good. If it were base64'd, you'd see it. >>> >>>> Btw, out of curiosity I have region max file size set to 1GB now, but >>>> what if I set it to say 10G or 50G? Is their significant overhead in >>>> address seeking via HDFS? >>>> >>> >>> You could do that. We don't have much experience running regions of >>> that size. You should for sure pre-split your table on creation if >>> you go this route (See HBaseAdmin API [1]). This method is not >>> available in shell so you'd have to script it or write a little java >>> to do it). >>> >>> St.Ack >>> >>> 1. >>> http://hbase.apache.org/docs/r0.89.20100726/apidocs/org/apache/hadoop/hbase/client/HBaseAdmin.html#createTable(org.apache.hadoop.hbase.HTableDescriptor, >>> byte[][]) >>> >>
