I thought HDFS will fix the namenode as a SPOF just as HBase fix the master in 0.20, so that is still not there yet?
On Tue, Jun 16, 2009 at 2:04 PM, Ryan Rawson <[email protected]> wrote: > HBase itself doesn't strictly have any SPOF in 0.20. Multiple master > failover, etc. > > HBase depends on HDFS, which does have a SPOF in it's namenode. If that > goes down, everything is down. Generally speaking, namenode is reliable, > but the hardware is the issue. You can have a quick recovery, but still > outage. > > > HBase isn't explicitly designed to run across a WAN split between 2 > datacenters. It's certainly possible, but during certain link-down > scenarios you are looking at cluster splits. HBase master will decide > those > regionservers no longer reachable have died, and HDFS will assume those > datanodes lost are gone, and start to replicate data. > > In HBase 0.21, we are hoping to have replication support between clusters. > > -ryan > > > On Tue, Jun 16, 2009 at 1:53 PM, Fred Zappert <[email protected]> wrote: > > > Hi, > > > > We're considering HBase for a customer-facing SaaS. I saw some > references > > to Master instance, and failure/failover scenarios on this list. > > > > We would be running this across at least two data centers in different > > cities or sates. > > > > Which leads to the following questions: > > > > 1. Are there any single points of failure in an HBase configuration. > > > > 2: What would be the impact of one data center being down? > > > > 3: What would be the recovery time and procedure to restore normal > > operation > > on a new master? > > > > There are approximately 4M transactions/day > > > > Thanks, > > > > Fred. > > >
