Well if you can afford a longer downtime, you can always distcp your existing hbase data. This way if things get screwed up you can always restore a 0.90.x on that old backup. You cannot distcp while the cluster is running since it will not be able to get locks on file (I think I faced that issue but not sure since I did this upgrade mid-2012).
When I did an upgrade, I brought up a test 0.94 cluster using the distcp backup (I took like 2-3 copies since I was very paranoid). Once I ran all my production jobs against the test instance and I was happy with all the results, that's when I re-ran the script to do the migration. It was all scripted out but I no longer have access to those scripts or else I would have shared it with you. Thanks, Viral On Tue, Feb 26, 2013 at 12:00 AM, Yusup Ashrap <[email protected]> wrote: > Hi Kiran , thanks for reply > From what I've read from online docs , downtime is inevitable for > upgrading from 0.90.2 to 0.94, > and I can afford some downtime. I cannot afford dataloss, so I am > concerning potential problems with rolling back to 0.90.2 if I fail to > upgrade. > > > -- > Best Regards > Yusup Ashrap > > > On Tuesday, February 26, 2013 at 3:53 PM, kiran wrote: > > > Hi, > > > > We also upgraded the version very recently. If you can afford couple of > > minutes downtime then you can safely bring down the cluster and do > upgrade. > > As such, there will be no data loss, but be careful with splits. The > > default split policy has been changed in this version if I am not wrong. > It > > causes some weird things. > > > > Thanks > > Kiran > > > > > > On Tue, Feb 26, 2013 at 1:03 PM, Yusup Ashrap <[email protected] (mailto: > [email protected])> wrote: > > > > > hi all, > > > I am updating production cluster from 0.90.2 to 0.94 . My table's size > is > > > about 20TB+ . > > > Scheduled update includes upgrading both hbase,hadoop version, > > > and I am also changing user with which I start up both hadoop and hbase > > > cluster from user "A" to user "B". > > > > > > It's production environment , so I wanted know what steps I should not > > > miss regarding this upgrade. > > > Table is kinda big and I don't have backup cluster to backup my data. > > > I wanted to know will there be a data loss scenario if I rollback after > > > having failed to upgrade. thanks. > > > > > > > > > > > > > > > > > > -- > > > Best Regards > > > Yusup Ashrap > > > > > > > > > > > -- > > Thank you > > Kiran Sarvabhotla > > > > -----Even a correct decision is wrong when it is taken late > >
