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From: Jonathan Ellis <jbellis@gmail.com>
Date: Thu, 3 Dec 2009 20:09:01 -0600
Message-ID: <e06563880912031809k3149b86fj659c7d10a1f3339b@mail.gmail.com>
Subject: Re: Removes increasing disk space usage in Cassandra?
To: cassandra-user@incubator.apache.org
Content-Type: text/plain; charset=ISO-8859-1

cassandra never modifies data in-place.  so it writes tombstones to
supress the older writes, and when compaction occurs the data and
tombstones get GC'd (after the period specified in your config file).

On Thu, Dec 3, 2009 at 8:07 PM, Ramzi Rabah <rrabah@playdom.com> wrote:
> Looking at jconsole I see a high number of writes when I do removes,
> so I am guessing these are tombstones being written? If that's the
> case, is the data being removed and replaced by tombstones? and will
> they all be deleted eventually when compaction runs?
>
>
>
> On Thu, Dec 3, 2009 at 3:18 PM, Ramzi Rabah <rrabah@playdom.com> wrote:
>> Hi all,
>>
>> I ran a test where I inserted about 1.2 Gigabytes worth of data into
>> each node of a 4 node cluster.
>> I ran a script that first calls a get on each column inserted followed
>> by a remove. Since I was basically removing every entry
>> I inserted before, I expected that the disk space occupied by the
>> nodes will go down and eventually become 0. The disk space
>> actually goes up when I do the bulk removes to about 1.8 gigs per
>> node. Am I missing something here?
>>
>> Thanks a lot for your help
>> Ray
>>
>