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MapReduce >> mail # user >> How bad is this? :)


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Re: How bad is this? :)
This is what I remember: If you disable journalling, running fsck
after a crash will (be required and) take longer. Certainly not a good
idea to have an extra wait after the cluster loses power and is being
restarted, etc.

On Tue, Jul 9, 2013 at 7:42 AM, Chris Embree <[EMAIL PROTECTED]> wrote:
> Hey Hadoop smart folks....
>
> I have a tendency to seek optimum performance given my understanding, so
> that led to me "brilliant" decision.  We settled on EXT4 for our underlying
> FS for HDFS.   Greedy for speed I thought, let's turn the journal off and
> gain the speed benefits.  After all, I have 3 copies of the data.
>
> How much does this bother you, given we have a 21 node prod and only 10 node
> dev cluster.
>
> I'm embarrassed to say I did not capture good pre and post change I/O.  In
> my simple brain, not writing to journal just screams improved I/O.
>
> Don't be shy, tell me how badly I have done bad things. (I originally said
> "screwed the pooch" but I reconsidered our > USA audience. ;)
>
> If I'm not incredibly wrong, should we consider higher speed (less safe)
> file systems?
>
> Correct/support my thinking.
> Chris

--
Harsh J