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From Jeremy Kepner <kep...@ll.mit.edu>
Subject Re: Accumulo defaults
Date Sat, 17 May 2014 21:27:01 GMT
walog provides data loss protection in a specific set of circumstances.
Most of our deployments are under a different set of circumstances.
Accumulo is only one part of our systems and we have other
mechanisms for protecting against the loss of data.
We find the walog actually becomes a bottleneck in certain circumstances
and so turning it off increases the overall reliability of our system.

On Sat, May 17, 2014 at 04:27:29PM -0400, Josh Elser wrote:
> You're likely to lose data in *any* deployment with the walogs turned off.
> 
> And, to reiterate what Sean says, I wouldn't really consider any
> benchmark with the walogs turned off valid except for "internal"
> benchmarks (ones where we evaluate components only within Accumulo
> for the sake of improving Accumulo itself and not comparing it to
> other systems).
> 
> On 5/17/14, 3:30 PM, Sean Busbey wrote:
> >You can set both of those in the accumulo-site.xml.
> >
> >However, it's going to be difficult to use benchmarks with walogs
> >disabled for valid comparisons to other systems. Also you are very
> >likely to lose data in any significantly sized deployment.
> >
> >
> >
> >On Sat, May 17, 2014 at 1:35 PM, Kepner, Jeremy - 0553 - MITLL
> ><kepner@ll.mit.edu <mailto:kepner@ll.mit.edu>> wrote:
> >
> >    As part of our Accumulo benchmarking we have decided to set certain
> >    values as defaults for all our databases:
> >
> >             tserver.compaction.minor.concurrent.max=5
> >             table.walog.enabled=false
> >
> >    We were wondering which file(s) we would need to modify to apply
> >    these defaults?
> >
> >
> >
> >
> >--
> >Sean

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