I see it is not so obvious and potentially dangerous so I will be learning & experimenting first. Thx for the tip.
2011/6/17 Steve Loughran <ste...@apache.org> > 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<ste...@apache.org> >> >> 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. >>> >>> >> >> >> > -- -MilleBii-
