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From Christopher <>
Subject Re: Sizing walog area
Date Wed, 23 Oct 2013 19:10:04 GMT
The data in the write-ahead logs is needed until the tserver flushes
the in memory maps to disk. Assuming you have a logger running on
every tserver, and tservers write to at least two loggers, you should
ensure that the size of the disk area is *at least* two times as big
as your in-memory map size per tserver. I'd say 5x-10x the in-memory
map size is probably safe. So, if your tservers are running with 2GB
of memory, then a 10-20GB area is probably more than sufficient.

Christopher L Tubbs II

On Wed, Oct 23, 2013 at 1:02 PM, Terry P. <> wrote:
> Greetings all,
> For Accumulo 1.4 where write ahead logs are not yet stored in HDFS, does
> anyone have guidancewith respect to sizing the walog area?  What exactly
> triggers when write ahead logs get removed?  What might cause them to hang
> around for an extended period of time (as in under abnormal circumstances)?
> The system this applies to will see an ingest rate of approximately 2000
> docs per second averaging 1-2K each (broken out into 12 columns each, so
> 24,000 entries per second) across 6 tabletserver nodes.
> Thanks in advance,
> Terry

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