: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different collectors with
different behaviors. Many of them do not collect every candidate on
every
-
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number
On Thu, Jun 16, 2011 at 12:48 AM, Terje Marthinussen
tmarthinus...@gmail.com wrote:
Even if the gc call cleaned all files, it is not really acceptable on a
decent sized cluster due to the impact full gc has on performance.
Especially non-needed ones.
Not acceptable as running GC on every
?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
mailto:jef...@gmail.com
To: user@cassandra.apache.org mailto:user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which
There's a ticket open to address this:
https://issues.apache.org/jira/browse/CASSANDRA-1974
-ryan
On Wed, Jun 15, 2011 at 8:49 AM, Terje Marthinussen
tmarthinus...@gmail.com wrote:
On Thu, Jun 16, 2011 at 12:48 AM, Terje Marthinussen
tmarthinus...@gmail.com wrote:
Even if the gc call
Even if the gc call cleaned all files, it is not really acceptable on a
decent sized cluster due to the impact full gc has on performance.
Especially non-needed ones.
You can run with -XX:+ExplicitGCInvokesConcurrent to safely trigger
CMS cycles. However that also means System.gc() semantics
-
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different
?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different collectors with
different behaviors. Many of them
I have a basic understanding of how Cassandra handles the file system (flushes
in Memtables out to SSTables, SSTables get compacted) and I understand that old
files are only deleted when a node is restarted, when Java does a GC, or when
Cassandra feels like it is running out of space.
My
You'd have to call system.gc via JMX.
https://issues.apache.org/jira/browse/CASSANDRA-2521 is open to
address this, btw.
On Thu, May 26, 2011 at 1:09 PM, Konstantin Naryshkin
konstant...@a-bb.net wrote:
I have a basic understanding of how Cassandra handles the file system
(flushes in
Actually this is no gaurantee. Its a common misunderstanding that
System.gc forces gc. It does not. It is a suggestion only. The vm always
has the option as to when and how much it gcs
On May 26, 2011 2:51 PM, Jonathan Ellis jbel...@gmail.com wrote:
It's a common misunderstanding that system.gc is only a suggestion; on
any VM you're likely to run Cassandra on, System.gc will actually
invoke a full collection.
On Thu, May 26, 2011 at 2:18 PM, Jeffrey Kesselman jef...@gmail.com wrote:
Actually this is no gaurantee. Its a common
Im sorry. This was my business at Sun. You are certainly wrong about
the Hotspot VM.
See this chapter of my book
http://java.sun.com/docs/books/performance/1st_edition/html/JPAppGC.fm.html#998394
On Thu, May 26, 2011 at 3:53 PM, Jonathan Ellis jbel...@gmail.com wrote:
It's a common
Some references...
An object enters an unreachable state when no more strong references
to it exist. When an object is unreachable, it is a candidate for
collection. Note the wording: Just because an object is a candidate
for collection doesn't mean it will be immediately collected. The JVM
is
I've read the relevant source. While you're pedantically correct re
the spec, you're wrong as to what the JVM actually does.
On Thu, May 26, 2011 at 3:14 PM, Jeffrey Kesselman jef...@gmail.com wrote:
Some references...
An object enters an unreachable state when no more strong references
to it
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different collectors with
different behaviors. Many of them do not collect every candidate on
every gc, but merely the easiest ones to find. This is why depending
on finalizers is a *bad*
Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different collectors with
different behaviors. Many of them do not collect every candidate on
every gc, but merely the easiest ones to find. This is why
Cassandra
to get rid of all of the extra space it is using on disk?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector
Is there a way for me to make (or even gently suggest to) Cassandra that it
may be a good time to free up some space?
Disregarding what's been said and until ref-counting is implemented this is
a useful tool to gently suggest cleanup:
https://github.com/ceocoder/jmxgc
On Thu, May 26, 2011 at
of all of the extra space it is using on disk?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been
?
- Original Message -
From: Jeffrey Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number
Kesselman jef...@gmail.com
To: user@cassandra.apache.org
Sent: Thursday, May 26, 2011 8:57:49 PM
Subject: Re: Forcing Cassandra to free up some space
Which JVM? Which collector? There have been and continue to be many.
Hotspot itself supports a number of different collectors with
different
For the purposes of clearing out disk space, you might also occasionally check
to see if you have snapshots that you no longer need. Certain operations
create snapshots (point-in-time backups of sstables) in the (default)
/var/lib/cassandra/data/keyspace_name/snapshots directory.
If you are
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