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From Jonathan Ellis <>
Subject Re: OOM Exception
Date Wed, 16 Dec 2009 23:18:50 GMT
What version are you using?  0.5 beta2 fixes the
using-more-memory-on-startup problem.

On Wed, Dec 16, 2009 at 5:16 PM, Brian Burruss <> wrote:
> i'll put my question first:
> - how can i determine how much RAM is required by cassandra?  (for normal operation
and restarting server)
> *** i've attached my storage-conf.xml
> i've gotten several more OOM exceptions since i mentioned it a week or so ago.  i started
from a fresh database a couple days ago and have been adding 2k blocks of data keyed off a
random integer at the rate of about 400/sec.  i have a 2 node cluster, RF=2, Consistency
for read/write is ONE.  there are ~70,420,082 2k blocks of data in the database.
> i used the default memory setup of Xmx1G when i started a couple days ago.  as the database
grew to ~180G (reported by unix du command) both servers OOM'ed at about the same time, within
10 minutes of each other.  well needless to say, my cluster is dead.  so i upped the memory
to 3G and the servers tried to come back up, but one died again with OOM.
> Before cleaning the disk and starting over a couple days ago, i played the game of "jack
up the RAM", but eventually i didn't want to up it anymore when i got to 5G.  the parameter,
SSTable.INDEX_INTERVAL, was discussed a few days ago that would change the number of "keys"
cached in memory, so i could modify that at the cost of read performance, but doing the math,
3G should be plenty of room.
> it seems like startup requires more RAM than just normal running.
> so this of course concerns me.
> i have the hprof files from when the server initially crashed and when it crashed trying
to restart if anyone wants them

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