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 http://gravatar.com/ctubbsii On Wed, Oct 23, 2013 at 1:02 PM, Terry P. <[email protected]> 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
