[performance] Crash recovery takes way too long
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                 Key: HBASE-1111
                 URL: https://issues.apache.org/jira/browse/HBASE-1111
             Project: Hadoop HBase
          Issue Type: Improvement
            Reporter: stack


Watching hbase recover from crashes, its taking way too long:

1. Must wait first on lease to expire (if server is rebooted, it should cancel 
the old servers' lease but make sure the lease expiration code runs)
2. Master splits logs.  This is single-threaded.  At least a maximum of 64 logs 
but seems to run slow anyways.
3. Assign out the regions that were on dead-server (minutes or even tens of 
minutes could have elapsed at this stage)
4. Wait on the regionservers to open.  If small cluster, because regionservers 
open regions in series, could take a long time opening a bunch of issues.  
Meantime the regions are not available, clients will likely timeout.
5. To make things worse, I've seen load-balancer cut in to 'help out' telling 
regionserver close some of its regions though its busy opening a bunch.

Andrew Purtell notes that HBASE-1110 will change a bunch of the above.

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