Ah ok. Thanks for clearing it JG. Regards,
Imran On Mon, May 17, 2010 at 11:10 PM, Jonathan Gray <jg...@facebook.com> wrote: > What you read from the slides was about removing HBase's SPOF, not Hadoop's. > > From 0.20, HBase doesn't have a SPOF in that you can have backup masters. In > more recent testing we've shown that while we support backup masters, there > are still circumstances where the second master won't know what to do and > your cluster could be left in an inconsistent state. > > That is being dealt with in 0.21 over in HBASE-2485. > > JG > >> -----Original Message----- >> From: Imran M Yousuf [mailto:imyou...@gmail.com] >> Sent: Monday, May 17, 2010 10:01 AM >> To: hbase-user@hadoop.apache.org >> Subject: Re: Availability Transaction and data integrity >> >> Thanks, my answers are inline too. >> >> On Mon, May 17, 2010 at 9:50 PM, Jonathan Gray <jg...@facebook.com> >> wrote: >> > Answers inline. >> > >> >> <snip /> >> >> * We will go live from January 2011, in that time frame should we >> >> develop using 0.21-SNAPSHOT or should we stick to 0.20.x? Ideally I >> >> would not want to go ahead with a snapshot in production and also >> >> would not want to make an upgrade within few months (because of some >> >> problems noticed in the mailing list regarding upgrade and I am a >> bit >> >> skeptical about it in general). >> > >> > If you need data durability (no data loss under node failure) then >> you have no choice but to go with 0.21 once it is released. This is >> not supported on the 0.20 line. >> > >> > There are a number of organizations who will be going live into >> production on 0.21 in Q3 2010. You can be sure that there will be a >> very well tested and stable 0.21 release by January 2011. >> > >> >> Extremely great! Then we are on the right track working with 0.21 >> >> >> * Transaction was a contrib module of HBase but it seems recently >> >> removed from the 0.21-SNAPSHOT. In light of it what would be the way >> >> to achieve transaction? >> > >> > It is still available but is being moved to GitHub. You can still >> use it, it has just been moved out of the core code. >> > >> >> * NN was (if I am not mistaken) a SPoF, I also learnt that its >> >> supposed to be fixed in 0.21, is that in trunk already? >> > >> > I'm not sure where you heard this was fixed in 0.21 as my >> understanding is that it is not fixed in 0.21. >> > >> > There is work being done at Facebook (and I believe parallel work >> being done elsewhere) to add a true backup NameNode. Once stabilized >> this will be released and available to the public though it may not be >> put into an official Hadoop release in an 0.21 timeframe. >> > >> >> I see, in that case I misunderstood the statement from Slide #10 of >> "ApacheCon2009: Practical HBase" - 'Removed SPoF, multi-master w/ >> automatic failover (ZK)'. What was this statement referring to as >> master? >> >> Great to learn that its being worked on.. >> >> >> * What kind of data loss should we design to? >> > >> > On 0.21, you should not have data loss. We are doing a lot of >> testing on this to ensure stability and durability. >> > >> >> This is extremely good news, it seems both my primary concerns are >> getting addressed! >> >> >> * Is there any professional service provider who could help us train >> >> for deployment, help optimize and in case we need emergency provide >> >> service? (P.S. I contacted Cloudera via email 11 days back and still >> >> waiting for a reply, may be they are not interested any alternate >> >> would do great!) >> > >> > Cloudera should be able to help. They're active on this list but >> perhaps don't want to use this forum to sell services. I would ping >> them again off the list. >> > >> >> Hmm, ok will try again with them. >> >> Thanks a lot! >> >> Imran >> >> >> >> >> I eagerly hope for some help and guideline on these queries. >> >> >> >> -- >> >> Imran M Yousuf >> >> Entrepreneur & Software Engineer >> >> Smart IT Engineering >> >> Dhaka, Bangladesh >> >> Email: im...@smartitengineering.com >> >> Blog: http://imyousuf-tech.blogs.smartitengineering.com/ >> >> Mobile: +880-1711402557 >> > >> >> >> >> -- >> Imran M Yousuf >> Entrepreneur & Software Engineer >> Smart IT Engineering >> Dhaka, Bangladesh >> Email: im...@smartitengineering.com >> Blog: http://imyousuf-tech.blogs.smartitengineering.com/ >> Mobile: +880-1711402557 > -- Imran M Yousuf Entrepreneur & Software Engineer Smart IT Engineering Dhaka, Bangladesh Email: im...@smartitengineering.com Blog: http://imyousuf-tech.blogs.smartitengineering.com/ Mobile: +880-1711402557
