I think you may want to think a bit about this… How far do you want to go with your memory management?
'Off heap' is a new nifty way of saying application level swap and memory management. So what you are basically saying is that I have memory, local persistence, then HDFS persistence. And your local persistence could be anything… (PCIe based flash, UltraDIMMs, RRAM (when it hits the market), SSDs, even raided spinning rust… ) If you’re going in that direction, what is tachyon doing? If you want to do this… and I’m not saying its a bad idea, you’ll want to think a bit more generic. Essentially its a layered hiearchy (memory, p1, p2, …) where p(n) is a pool of devices which have a set of rules on how to propagate pages up or down the hierarchy. > On Jun 29, 2015, at 1:20 AM, Jean-Marc Spaggiari <jean-m...@spaggiari.org> > wrote: > > Hi, > > Is it possible to have 2 bucket cache on a single region server? > > Like L2 and L3? I would like to have L2 offheap and block evicted from L2 > going into L3 on SSD. So we already have something like that? Or should I > open a JIRA? > > hbase.bucketcache.ioengine can get only one value. Might be nice to have a > flume-like approach... > > hbase.bucketcache=myoffheap,myssddrive > hbase.bucketcache.myoffheap.ioengine=offheap > hbase.bucketcache.myssddrive.ioengine=file://my_ssd_mnt/there > > And keep the order specified in hbase.bucketcache, so myoffheap=L2, > myssddrive=L3, etc.? > > Thanks, > > JM The opinions expressed here are mine, while they may reflect a cognitive thought, that is purely accidental. Use at your own risk. Michael Segel michael_segel (AT) hotmail.com
