The client's retry policies need some more thoughts, currently it's hard to manage.
https://issues.apache.org/jira/browse/HBASE-2445 J-D On Thu, Jul 8, 2010 at 5:17 PM, <[email protected]> wrote: > Thankyou JG..Did not realize ZK is sensitive to IO..also did n't plan for > more than normal disk space.. > I was thinking around 5 ZK on relatively cheap hardware just to support our > insert/put rates (300 million per day roughly) > ...NN/HM/DN/HM all on much more powerful machines (penguin like hardware) > Does that sound ok? > > Besides scaling..I've a question regarding retries... > hbase.client.retries.number > zookeeper.retries > > While testing from hbase client (tomcat in our case), by default client keeps > trying for ever connecting to zookeeper.. > if all are down..It does n't abort after 10 (hbase.client.retries.number) or > zookeeper.retries (i think default 5).. > > Only way i can stop retrying is if set hbase.client.retries.number = 0 > (zookeper.retries can be any number) > From config comment, I see that there is exponential backoff algorithm..could > you please shed some light on retries? > I'll read about the algorithm as well.. > > Is there a way to completely stop retrying after X absolute tries.? > > thanks > venkatesh > > > PS: I'll get on IRC after my critical questions :)..sorry > > > > > > > -----Original Message----- > From: Jonathan Gray <[email protected]> > To: [email protected] <[email protected]> > Sent: Thu, Jul 8, 2010 7:24 pm > Subject: RE: zookeeper & HBase > > > ZK is sensitive to IO starvation which is why it is recommended to keep it on > a > > separate node or separate disk. In most cases, giving ZK its own disk is > > sufficient and dedicated node(s) are unnecessary. > > > > On smallish clusters like 10 nodes, I would recommend starting with just 1 ZK > > node co-located with your NameNode and HMaster, but with a dedicated disk just > > for ZK. Since the NN is a SPOF, having one ZK doesn't really lower your fault > > tolerance, except that it may be on a non-raided disk. I encourage RAID usage > > for NN and ZK. JBOD for DN/RS. > > > > JG > > > >> -----Original Message----- > >> From: [email protected] [mailto:[email protected]] > >> Sent: Thursday, July 08, 2010 4:20 PM > >> To: [email protected] > >> Subject: zookeeper & HBase > >> > >> > >> I'm trying to have our deployment layout..I read one of the > >> articles/FAQ (probably JG's)...that it's better to > >> have zookeeper on separate cluster/separate sets of machine..I'm > >> assuming that is the right approach.. > >> > >> > >> All our transactions are HBase (inserts, mapreduce-table as input, > >> another table as output, other queries,..) > >> Based on other thread on locality..RegionServer & Datanode i'll put on > >> same hosts.. > >> > >> If these boxes have enough capacity, do we need to put zookeeper on > >> separate cluster? > >> If it is on a separate cluster, my understanding is zookeper has much > >> smaller memory footprint compared > >> to HRegionServer/Datanodes..& it shld need that much CPU as > >> well..correct? > >> > >> Is there any suggested guidance on number of zookeeper vs number of > >> regionservers?..looking for some ratio..say 10 node cluster.. > >> how many zookeeper..? > >> > >> Please ignore responding to this ..if this is outside the etiquette > >> thanks > >> venkatesh > >> > > > >
