Also I think we should make it more clear (on the front page) that HBase requires the append branch and provide a link to that as well.
Cosmin On Jun 3, 2011, at 3:23 PM, Brian Bockelman wrote: > A meta-comment here (triggered by Praveenesh's comments about not wanting to > re-install): > > If you have to install the same software on more than one piece of software, > you really ought to automate it. In the long run, you'll save more time if > you can instantly roll out changes than manually doing it. In all > likelihood, if you're going to be working with a piece of software > (Hadoop-based or not!), you'll re-install it a few times. > > The install of HDFS should take roughly the same amount of time on 2, 20, or > 200 nodes. > > Brian > > On Jun 3, 2011, at 6:47 AM, Andrew Purtell wrote: > >>> Is *Hadoop 0.20.2 also not compatible with Hbase 0.90.3 ???* >> >> In a strict sense they are, but without append support HBase cannot >> guarantee that the last block of write ahead logs are synced to disk, so in >> some failure cases edits will be lost. With append support then the "hole" >> of these failure cases is closed. Also append branch adds a change to lease >> recovery that allows the HBase Master to take ownership of regionserver logs >> in order to split them quickly. (Without this patch you may be waiting 10 >> minutes for lease recovery...) So these differences are clearly important >> for durability and fault recovery in a realistic time frame. >> >> A full reinstallation is not necessary. >> >> You can take the Hadoop core jar packaged in lib/ of HBase 0.90.3 and >> replace every Hadoop core jar on your cluster with them. >> >> OR >> >> You can compile 0.20-append and just replace the Hadoop core jar everywhere >> with the result, including the one in the HBase lib/. >> >> - Andy >> >> --- On Fri, 6/3/11, praveenesh kumar <[email protected]> wrote: >> >>> From: praveenesh kumar <[email protected]> >>> Subject: Does Hadoop 0.20.2 and HBase 0.90.3 compatible ?? >>> To: [email protected], [email protected] >>> Date: Friday, June 3, 2011, 3:37 AM >>> Guys, >>> >>> I am in a very big big confusion. Please.. I really need >>> your feedbacks and >>> suggestions.. >>> >>> The scenario is like this... >>> >>> I set up *Hadoop 0.20.2 cluster* of *12 nodes*.. >>> >>> Now I set up* Hbase 0.90.3* *12 node cluster* on top >>> of it. >>> >>> But after all that experimenting and struggling.. I read >>> the following SHOCKING line on my Hbase web UI >>> >>> ---* " You are currently running the HMaster without HDFS append support >>> enabled. This may result in data loss. Please see the HBase wiki for >>> details. "* >>> >>> And when I searched more about it.. I found Michael G. Nolls article.. >>> saying that *Hadoop 0.20.2 and Hbase 0.90.2 are not compatible*. >>> >>> Is *Hadoop 0.20.2 also not compatible with Hbase 0.90.3 ???* >>> >>> So does it means I have to re-install hadoop 0.20. >>> append if I want to use Hbase. >>> >>> I did a lot of struggle to reach upto this stage.. do I >>> have to do all of it again.. ?? >>> >>> Is there any other work around solution.. of not >>> re-installing everything again ?? >>> >>> Please help..!!! :-( >>> >>> Thanks, >>> Praveenesh >>> >
