> Thanks for this very helpful info. It is indeed a production site which I
> cannot easily upgrade. I will try the various gc knobs and post any positive
> results.
*IF* your data size, or at least hot set, is small enough that you're
not extremely reliant on the current size of page cache, and
:23
To: user@cassandra.apache.org
Subject: Re: Garbage collection freezes cassandra node
> On node "172.16.107.46", I see the following:
>
> 21:53:27.192+0100: 1335393.834: [GC 1335393.834: [ParNew (promotion failed):
> 319468K->324959K(345024K), 0.1304456 secs]13353
> On node "172.16.107.46", I see the following:
>
> 21:53:27.192+0100: 1335393.834: [GC 1335393.834: [ParNew (promotion failed):
> 319468K->324959K(345024K), 0.1304456 secs]1335393.964: [CMS:
> 6000844K->3298251K(8005248K), 10.8526193 secs] 6310427K->3298251K(8350272K),
> [CMS Perm : 26355K->263
tested the "XX:+DisableExplicitGC" switch.
>
> Is the right thing to do to decrease the CMSInitiatingOccupancyFraction
> setting?
>
> Thanks!
>
> Rene
>
> -Original Message-
> From: sc...@scode.org [mailto:sc...@scode.org] On Behalf Of Peter Schuller
> Sent: d
uot; switch.
Is the right thing to do to decrease the CMSInitiatingOccupancyFraction setting?
Thanks!
Rene
-Original Message-
From: sc...@scode.org [mailto:sc...@scode.org] On Behalf Of Peter Schuller
Sent: dinsdag 20 december 2011 6:38
To: user@cassandra.apache.org
Subject: Re: Garb
] On Behalf Of Peter Schuller
Sent: dinsdag 20 december 2011 6:36
To: user@cassandra.apache.org
Subject: Re: Garbage collection freezes cassandra node
> During the garbage collections, Cassandra freezes for about ten seconds. I
> observe the following log entries:
>
>
>
> “GC for C
I should add: If you are indeed actually pausing due to "promotion
failed" or "concurrent mode failure" (which you will see in the GC log
if you enable it with the options I suggested), the first thing I
would try to mitigate is:
* Decrease the occupancy trigger (search for "occupancy") of CMS to
> During the garbage collections, Cassandra freezes for about ten seconds. I
> observe the following log entries:
>
>
>
> “GC for ConcurrentMarkSweep: 11597 ms for 1 collections, 1887933144 used; max
> is 8550678528”
Ok, first off: Are you certain that it is actually pausing, or are you
assumin
Increasing memory in this case may not solve the problem. Share some
information about your workload. Cluster configuration, cache sizes etc.
You can also try getting java heap historgram to get more info on what's on
the heap.
On Mon, Dec 19, 2011 at 7:35 AM, Rene Kochen
wrote:
> I recently se
2011 16:35
An: user@cassandra.apache.org
Betreff: Garbage collection freezes cassandra node
I recently see the following garbage collect behavior in our performance tests
(the attached chart shows the heap-size in MB):
[cid:image001.jpg@01CCBE73.8B567F80]
During the garbage collections, Cassandra
Giving it more memory will simply increase the time between (and duration
of) the freezes. Which JVM are you using? I think that Java 7 has some nice
improvements to GC especially with large heaps.
On Mon, Dec 19, 2011 at 7:35 AM, Rene Kochen
wrote:
> I recently see the following garbage collect
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