On Tue, May 31, 2011 at 2:15 AM, Sreehari G <sreehar...@huawei.com> wrote:
> Hi Todd , > > Steps to reproduce : > > 1) Configure n>1 ,say 3 name dirs > 2) Upgrade Namenode - After upgrade is over for 1st dir , stop/kill > the namenode > Are you running the "upgrade" command with 0.21? > 3) Start namenode and write some files (delta) & then stop > Which version do you restart with? 0.21 again or 0.20? > 4) Rollback namenode > Which version do you run the rollback command with? > > Now , after (4) , namenode will start normally , but it will contain the > delta , since the unrollbacked 2nd dir will be the latest one (with the > greatest checkpointtime ) & during savenamespace during loadFSImage() , the > 2nd dir image will be saved to all the 3 dirs .. > > The system could 've gone back to the state before rollback - a FAILED > Rolback which i think would 've been fine rather than the current behaviour > .. > > I'am using 20.1 , but I verified in latest trunk also .. > > > -- Sreehari > > HUAWEI TECHNOLOGIES CO.,LTD. [image: huawei_logo] > > > Solitaire > Domlur > Bangalore > www.huawei.com > > ------------------------------------------------------------------------------------------------------------------------------------- > This e-mail and its attachments contain confidential information from > HUAWEI, which > is intended only for the person or entity whose address is listed above. > Any use of the > information contained herein in any way (including, but not limited to, > total or partial > disclosure, reproduction, or dissemination) by persons other than the > intended > recipient(s) is prohibited. If you receive this e-mail in error, please > notify the sender by > phone or email immediately and delete it! > > > ------------------------------ > *From:* Todd Lipcon [mailto:t...@cloudera.com] > *Sent:* Monday, May 30, 2011 9:56 PM > *To:* hdfs-dev@hadoop.apache.org; sreehar...@huawei.com > *Subject:* Re: Expectation during Rollback after a partially failed > Upgrade .. Should DELTA be visible ? > > Hi Sreehari, > > Which versions are you using for this test? > > In step 1 below, how does the upgrade fail? Can you provide specific steps > to reproduce? > > Smells like a bug to me, if I understand the scenario correctly. > > -Todd > > On Mon, May 30, 2011 at 5:29 AM, Sreehari G <sreehar...@huawei.com> wrote: > >> Hi all , >> >> What is the expectation in the following scenario : >> >> Namenode has 3 name dirs configured .. >> 1) Namenode upgrade starts - Upgrade fails after 1st directory is upgraded >> (2nd and 3rd dir is left unchanged ..) >> 2) Namenode starts >> 3) Namenode shutdown and rollbacked >> >> Are the new changes done meant to be visible ? With current implementation >> , after a rollback new changes are visible .. Is this expected ?? >> >> As per my observation , since Namenode is saving the latest image dir(the >> upgraded 1st dir since checkpointtime is incremented during upgrade for this >> dir) will be loaded and saved to all dirs during loadfsimage .. >> >> But if a ROLLBACK is done , the 1st dir will be rolled back (the older >> copy becomes current and its checkpointtime is now LESS than other dirs ..) >> and others left behind since they dont contain previous .. Now during >> loadfsimage , the 2nd dir will be selected since it has the highest >> checkpoint time and saved to all dirs (including 1st ) .. Now due to this , >> the new changes b/w UPGRADE and ROLLBACK DELTA present in 2nd dir gets >> reflected even after ROLLBACK .. >> >> Is this expected ? I ask this since : >> >> 1) this is not the case with a SUCCESSFULL Upgrade/Rollback (New changesare >> lost >> after rollback).. & >> 2) In Hadoop-702 (DFS Upgrade Proposal) , FSStateTransition7.htm says { >> r0. if previous directory does not exist then fail rollback } , but it >> continues in the current implementation .. >> >> >> >> Regards , >> >> Sreehari >> >> HUAWEI TECHNOLOGIES CO.,LTD. [image: huawei_logo] >> >> >> Solitaire >> Domlur >> Bangalore >> www.huawei.com >> >> ------------------------------------------------------------------------------------------------------------------------------------- >> This e-mail and its attachments contain confidential information from >> HUAWEI, which >> is intended only for the person or entity whose address is listed above. >> Any use of the >> information contained herein in any way (including, but not limited to, >> total or partial >> disclosure, reproduction, or dissemination) by persons other than the >> intended >> recipient(s) is prohibited. If you receive this e-mail in error, please >> notify the sender by >> phone or email immediately and delete it! >> >> > > > > -- > Todd Lipcon > Software Engineer, Cloudera > -- Todd Lipcon Software Engineer, Cloudera
