Lzo of image data, which is already Jpeg? Probably not a great idea, yes? -Jack
On Wed, Sep 22, 2010 at 11:06 AM, Stack <[email protected]> wrote: > Are you lzo'ing Jack? If not, you probably should. > St.Ack > > On Wed, Sep 22, 2010 at 3:17 AM, Jack Levin <[email protected]> wrote: >> 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[][]) >>>>> >>>> >> >
