Hello Aaron,
I happen to have 48GB on each machines I use in the cluster. Can I
assume that I can't really use all of this memory productively? Do you
have any suggestion related to that? Can I run more than one instance on
Cassandra on the same box (using different ports) to take advantage
Are you using cassandra's caching? If you are then you will need to play
around with the RAM setting to find a sweet spot. A low hit rate on the
cache (which is counter productive anyway) will cause more GC. A high hit
rate, less GC.
If you are not caching, no need to use a large heap as the
On 10/20/2011 09:38 AM, Maxim Potekhin wrote:
I happen to have 48GB on each machines I use in the cluster. Can I
assume that I can't really use all of this memory productively? Do you
have any suggestion related to that? Can I run more than one instance on
Cassandra on the same box (using
I see the following in my GC log
1910.513: [GC [1 CMS-initial-mark: 2598619K(26214400K)]
13749939K(49807360K), 6.0696680 secs] [Times: user=6.10 sys=0.00,
real=6.07 secs]
so there is a stop-the-world period of 6 seconds. does this sound bad
? or 6 seconds is OK and we should expect the built-in
It does seem long and will be felt by your application.
Are you running a 47GB heap ? Most peeps seem to think 8 to 12 is about the
viable maximum.
Cheers
-
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com
On 25/09/2011, at 7:14 PM, Yang
I see the following in my GC log
1910.513: [GC [1 CMS-initial-mark: 2598619K(26214400K)]
13749939K(49807360K), 6.0696680 secs] [Times: user=6.10 sys=0.00,
real=6.07 secs]
so there is a stop-the-world period of 6 seconds. does this sound bad
? or 6 seconds is OK and we should expect the
Thanks Peter and Aaron.
right now I have too much logging so the CMS logging is flushed
(somehow it does not appear in the system.log, only on stdout ), I'll
keep an eye on the correlation with ParNew as I get more logging
Yang
On Sun, Sep 25, 2011 at 3:59 AM, Peter Schuller
