On Sun, Mar 1, 2015 at 12:57 AM, donhoff_h <[email protected]> wrote: > Hi, experts > > I am using HBase0.98.10 and have 3 problems about BucketCache > configuration. > > First: > I read the reference guide of Apache HBase to learn how to config > BucketCache. I find that when using offheap BucketCache, the reference > guide says that I should config the HBASE_OFFHEAPSIZE , it also says that > I should config -XX:MaxDirectMemorySize. Since these two parameters are > both related to the DirectMemory, I am confused which one should I > configure? > > See bin/hbase how HBASE_OFFHEAPSIZE gets interpolated as value of the -XX:MaxDirectMemorySize passed to java (so set HBASE_OFFHEAPSIZE) (will fix the doc so more clear)
> Second: > I want to know how to configure the BucketCache as a pure secondary > cache, which I mean to bypass the CombinedBlockCache policy. I tried to > configure as following , but when I go to the regionserver's webUI, I > found it says "No L2 deployed" > > hbase.bucketcache.ioengine=offheap > hbase.bucketcache.size=200 > hbase.bucketcache.combinedcache.enabled=false > > What do you mean by pure secondary cache? Which block types do you want in the bucketcache? Why bypass CBC? We've been trying to simplify bucketcache deploy. Part of this streamlining has been removing the myriad options because they tend to confuse and give user a few simple choices. Do the options not work for you? > Third: > I made the following configuration to set the Bucket Sizes. But from > regionserver's WebUI, I found that (4+1)K and (8+1)K sizes are used, > (64+1)K sizes are not used. What's wrong with my configuration? > hbase.bucketcache.ioengine=offheap > hbase.bucketcache.size=200 > hbase.bucketcache.combinedcache.enabled=true > hbase.bucketcache.sizes=65536 hfile.block.cache.sizes=65536 I configured > these two both for I don't know which one is in use now. > > As per previous mail (and HBASE-13125), hfile.block.cache.sizes has no effect in 0.98.x. Also per our previous mail "Questions about BucketCache", isn't it hbase.bucketcache.bucket.sizes that you want? You have tried the defaults and they do not fit your access patten? Yours, St.Ack > Many Thanks!
