The design is such that running multiple secondary namenodes should not corrupt the image (modulo any bugs). Are you seeing image corruptions when this happens?
You can run all or any daemons in 32-bit mode or 64 bit-mode. You can mix-and-match. If you have many millions of files, then you might want to allocte more than 3GB heap space to the namenode and secondary namenode. In that case, you will jave to run the namenode and secondary namenode using 64 bit JVM. dhruba On Tue, Nov 25, 2008 at 4:39 PM, lohit <[EMAIL PROTECTED]> wrote: > Well, if I think about, image corruption might not happen, since each > checkpoint initiation would have unique number. > > I was just wondering what would happen in this case > Consider this scenario. > Time 1 <-- SN1 asks NN image and edits to merge > Time 2 <-- SN2 asks NN image and edits to merge > Time 2 <-- SN2 returns new image > Time 3 <-- SN1 returns new image. > I am not sure what happens here, but its best to test it out before setting > up something like this. > > And if you have multiple entries in NN file, then one SNN checkpoint would > update all NN entries, so redundant SNN isnt buying you much. > > Thanks, > Lohit > > > > ----- Original Message ---- > From: Sagar Naik <[EMAIL PROTECTED]> > To: core-user@hadoop.apache.org > Sent: Tuesday, November 25, 2008 4:32:26 PM > Subject: Re: 64 bit namenode and secondary namenode & 32 bit datanode > > > > lohit wrote: > > I might be wrong, but my assumption is running SN either in 64/32 > shouldn't matter. > > But I am curious how two instances of Secondary namenode is setup, will > both of them talk to same NN and running in parallel? > > what are the advantages here. > > > I just have multiple entries master file. I am not aware of image > corruption (did not take look into it). I did for SNN redundancy > Pl correct me if I am wrong > Thanks > Sagar > > Wondering if there are chances of image corruption. > > > > Thanks, > > lohit > > > > ----- Original Message ---- > > From: Sagar Naik <[EMAIL PROTECTED]> > > To: core-user@hadoop.apache.org > > Sent: Tuesday, November 25, 2008 3:58:53 PM > > Subject: 64 bit namenode and secondary namenode & 32 bit datanode > > > > I am trying to migrate from 32 bit jvm and 64 bit for namenode only. > > *setup* > > NN - 64 bit > > Secondary namenode (instance 1) - 64 bit > > Secondary namenode (instance 2) - 32 bit > > datanode - 32 bit > > > > From the mailing list I deduced that NN-64 bit and Datanode -32 bit combo > works > > But, I am not sure if S-NN-(instance 1--- 64 bit ) and S-NN (instance 2 > -- 32 bit) will work with this setup. > > > > Also, do shud I be aware of any other issues for migrating over to 64 bit > namenode > > > > Thanks in advance for all the suggestions > > > > > > -Sagar > > > > >
