On 16/06/11 14:19, MilleBii wrote:
But if my Filesystem is up& running fine... do I have to worry at all or
will the copy (ftp transfer) of hdfs will be enough.
I'm not going to make any predictions there as if/when things go wrong
-you do need to shut down the FS before the move
-you ought to get the edit logs replayed before the move
-you may want to try experimenting with copying the namenode data and
bringing up the namenode (without any datanodes connected to, so it
comes up in safe mode), to make sure everything works.
I'd also worry that if you aren't familiar with the edit log, you may
need to spend some time learning the subtle details of namenode
journalling, replaying, backup and restoration, and what the secondary
namenode does. It's easy to bring up a cluster and get overconfident
that it works, right up to the moment it stops working. Experiment with
your cluster's and teams' failure handling before you really need it
2011/6/16 Steve Loughran<[email protected]>
On 15/06/11 15:54, MilleBii wrote:
Thx.
#1 don't understand the "edit logs" remark.
well, that's something you need to work on as its the key to keeping your
cluster working. The edit log is the journal of changes made to a namenode,
which gets streamed to HDD and your secondary Namenode. After a NN restart,
it has to replay all changes since the last checkpoint to get its directory
structure up to date. Lose the edit log and you may as well reformat the
disks.
