This version of 0.90.x HBase can be started on data written by HBase 0.20.x or HBase 0.89.x. There is no need of a migration step. HBase 0.89.x and 0.90.x does write out the name of region directories differently -- it names them with a md5 hash of the region name rather than a jenkins hash -- so this means that once started, there is no going back to HBase 0.20.x.
Be sure to remove the hbase-default.xml
from
your conf
directory on upgrade. A 0.20.x version of this file will have
sub-optimal configurations for 0.90.x HBase. The
hbase-default.xml
file is now bundled into the
HBase jar and read from there. If you would like to review
the content of this file, see it in the src tree at
src/main/resources/hbase-default.xml
or
see ???.
Finally, if upgrading from 0.20.x, check your
.META.
schema in the shell. In the past we would
recommend that users run with a 16kb
MEMSTORE_FLUSHSIZE
.
Run hbase> scan '-ROOT-'
in the shell. This will output
the current .META.
schema. Check
MEMSTORE_FLUSHSIZE
size. Is it 16kb (16384)? If so, you will
need to change this (The 'normal'/default value is 64MB (67108864)).
Run the script bin/set_meta_memstore_size.rb
.
This will make the necessary edit to your .META.
schema.
Failure to run this change will make for a slow cluster [12]
.