I've run into this with large shuffles - I assumed that there was
contention between the shuffle output files and the JVM for memory.
Whenever we start getting these fetch failures, it corresponds with high
load on the machines the blocks are being fetched from, and in some cases
complete unresponsiveness (no ssh etc). Setting the timeout higher, or the
JVM heap lower (as a percentage of total machine memory) seemed to help..
On Mon, Sep 22, 2014 at 8:02 PM, Christoph Sawade <
christoph.saw...@googlemail.com> wrote:
> Hey all. We had also the same problem described by Nishkam almost in the
> same big data setting. We fixed the fetch failure by increasing the timeout
> for acks in the driver:
>
> set("spark.core.connection.ack.wait.timeout", "600") // 10 minutes timeout
> for acks between nodes
>
> Cheers, Christoph
>
> 2014-09-22 9:24 GMT+02:00 Hortonworks <zzh...@hortonworks.com>:
>
> > Actually I met similar issue when doing groupByKey and then count if the
> > shuffle size is big e.g. 1tb.
> >
> > Thanks.
> >
> > Zhan Zhang
> >
> > Sent from my iPhone
> >
> > > On Sep 21, 2014, at 10:56 PM, Nishkam Ravi <nr...@cloudera.com> wrote:
> > >
> > > Thanks for the quick follow up Reynold and Patrick. Tried a run with
> > > significantly higher ulimit, doesn't seem to help. The executors have
> > 35GB
> > > each. Btw, with a recent version of the branch, the error message is
> > "fetch
> > > failures" as opposed to "too many open files". Not sure if they are
> > > related. Please note that the workload runs fine with head set to
> > 066765d.
> > > In case you want to reproduce the problem: I'm running slightly
> modified
> > > ScalaPageRank (with KryoSerializer and persistence level
> > > memory_and_disk_ser) on a 30GB input dataset and a 6-node cluster.
> > >
> > > Thanks,
> > > Nishkam
> > >
> > > On Sun, Sep 21, 2014 at 10:32 PM, Patrick Wendell <pwend...@gmail.com>
> > > wrote:
> > >
> > >> Ah I see it was SPARK-2711 (and PR1707). In that case, it's possible
> > >> that you are just having more spilling as a result of the patch and so
> > >> the filesystem is opening more files. I would try increasing the
> > >> ulimit.
> > >>
> > >> How much memory do your executors have?
> > >>
> > >> - Patrick
> > >>
> > >> On Sun, Sep 21, 2014 at 10:29 PM, Patrick Wendell <pwend...@gmail.com
> >
> > >> wrote:
> > >>> Hey the numbers you mentioned don't quite line up - did you mean PR
> > 2711?
> > >>>
> > >>> On Sun, Sep 21, 2014 at 8:45 PM, Reynold Xin <r...@databricks.com>
> > >> wrote:
> > >>>> It seems like you just need to raise the ulimit?
> > >>>>
> > >>>>
> > >>>> On Sun, Sep 21, 2014 at 8:41 PM, Nishkam Ravi <nr...@cloudera.com>
> > >> wrote:
> > >>>>
> > >>>>> Recently upgraded to 1.1.0. Saw a bunch of fetch failures for one
> of
> > >> the
> > >>>>> workloads. Tried tracing the problem through change set analysis.
> > Looks
> > >>>>> like the offending commit is 4fde28c from Aug 4th for PR1707.
> Please
> > >> see
> > >>>>> SPARK-3633 for more details.
> > >>>>>
> > >>>>> Thanks,
> > >>>>> Nishkam
> > >>
> >
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