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From: Henry Luo <hluo@choicestream.com>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Date: Thu, 14 Oct 2010 20:36:16 -0400
Subject: RE: Hundreds compaction a day, is it normal?
Thread-Topic: Hundreds compaction a day, is it normal?
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Thanks for the advice.  Follow up questions:

a) is 0.6.6 compactable with 0.6.1? Do we need to change the config? How ab=
out the data in the current system?

b) Should we wait for 0.7? If so, same questions above.

Thanks.
Henry

-----Original Message-----
From: Jonathan Ellis [mailto:jbellis@gmail.com]
Sent: Thursday, October 14, 2010 4:33 PM
To: user
Subject: Re: Hundreds compaction a day, is it normal?

a) 0.6.1 is ancient, upgrade to 0.6.6 (see
http://www.riptano.com/blog/whats-new-cassandra-066 for links to all
the improvements since 0.6.1 -- the links to older versions are at the
bottom)

b) increase the memtable flush thresholds to reduce the need for
compaction (8x the defaults is a decent starting point, assuming you
are giving a reasonable amount of your 32GB to the JVM for heap)

c) set compaction priority lower
(http://www.riptano.com/blog/cassandra-annotated-changelog-063) to
make compaction hurt less

d) enable the dynamic snitch
(http://www.riptano.com/blog/whats-new-cassandra-065) to route around
nodes that are slow b/c of compaction

On Thu, Oct 14, 2010 at 3:23 PM, Henry Luo <hluo@choicestream.com> wrote:
> We have a five node cluster, using replication factor of 3.  The applicat=
ion
> is only sending write requests at this point - we'd like to gain some
> operation experience with it first before start read from it.
>
>
>
> We are seeing over a hundred compaction activities on each server, some o=
f
> them are for HintsColumnFamily.
>
>
>
> Each machine has 32 GB memory, two disk arrays, one with raid 0 for commi=
t
> log, one with raid 5 for data. We are using version 0.6.1, and pretty muc=
h
> the out of the box storage.xml.
>
>
>
> Is this normal? Where should we look for tuning?
>
>
>
> Here is the ring info
>
>
>
> Address       Status     Load
> Range                                      Ring
>
>
> 103348149328693428942388257816272166328
>
> 10.100.10.68  Up         136.41 GB
> 62116456964768051843784433654721163092     |<--|
>
> 10.100.10.64  Up         136.31 GB
> 82105179051854269619799333828977372565     |   ^
>
> 10.100.10.66  Up         152.77 GB
> 92197953251627500070365755299174650936     v   |
>
> 10.100.10.72  Up         71.38 GB
> 102264937228017528105060257264614100661    |   ^
>
> 10.100.10.76  Up         24.8 GB
> 103348149328693428942388257816272166328    |-->|
>
>
>
> Thanks.
>
> Henry
>
>
>
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--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

The information transmitted is intended only for the person or entity to wh=
ich it is addressed and may contain confidential, proprietary, and/or privi=
leged material. Any review, retransmission, dissemination or other use of, =
or taking of any action in reliance upon this information by persons or ent=
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 in error, please contact the sender and delete the material from all compu=
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