If you have a mirror of your production environment (not in size but in versions of hardware and software), I suggest you run migration steps on this environment to test and measure the down times.
Actual down times are dependent on components in use. You could also do some of your backup steps by pushing namenode to safemode (which is still down time of your cluster, but you could still be able to do some readonly operations on the cluster) That said, we migrated some large clusters in couple of hours but spent days upgrading and rolling back test environments before production environments. Also consider automating what ever you can when working of the test environment. Ravi On Thu, Jan 16, 2014 at 6:14 AM, Nirmal Kumar <[email protected]>wrote: > All, > > > > I want to know while upgrading\migrating from Apache Hadoop 1.x to > 2.x(MRv2+YARN) in a production cluster of several nodes is there any > **anticipated > downtime** that one needs to be aware of? > > I am asking this since this will hamper the **HA (High Availability)**. > > > > IMHO as with any other upgrade\migrate process, it will have some **manual > steps**(sanity checks, backups) and need **thorough testing** before > going live. > > > > > Please share your opinions on any other reasons for the downtime. > > > > Thanks, > > -Nirmal > > ------------------------------ > > > > > > > NOTE: This message may contain information that is confidential, > proprietary, privileged or otherwise protected by law. The message is > intended solely for the named addressee. If received in error, please > destroy and notify the sender. Any use of this email is prohibited when > received in error. Impetus does not represent, warrant and/or guarantee, > that the integrity of this communication has been maintained nor that the > communication is free of errors, virus, interception or interference. > -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
