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  You cannot migrate unless all has been major compacted first.  Major 
compaction is necessary because the way deletes work changed in 0.20 hbase.
  
- -ROOT- and .META. flush frequently so could mess up your nice and tidy 
single-file per store major_compacted hbase layout.  They won't flush if there 
have not been edits.  So, make sure your cluster is not taking writes and 
hasn't been doing so for a good while before starting up the major compaction 
process.
+ -ROOT- and .META. flush frequently so could mess up your nice and tidy 
single-file per store major_compacted hbase layout.  They won't flush if there 
have not been edits.  So, make sure your cluster is not taking writes and 
hasn't been doing so for a good while before starting up the major compaction 
process.  Getting your cluster to shutdown with one file only in -ROOT- and 
.META. may be a bit tough so to help, facility has been added to the HEAD of 
the 0.19 branch that will allow you major compact catalog regions in a shutdown 
hbase.  This facility only works on the -ROOT- and .META. catalog tables, not 
on user space tables.  For usage, type:
  
- TODO: Command-line tool to major compact an offline cluster.
+ {{{./bin/hbase org.apache.hadoop.hbase.regionserver.HRegion}}}
  
  ==== Migrating ====
  

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