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Date: Tue, 29 Mar 2011 17:19:49 +0800
Message-ID: <AANLkTi=Vsg-a9-pyD4=fkEiHv-L85hV5CrteiE9+UAfF@mail.gmail.com>
Subject: Re: Compaction doubles disk space
From: Sheng Chen <chensheng2010@gmail.com>
To: user@cassandra.apache.org
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>From a previous thread of the same topic, I used a force GC and the extra
spaces are released.

What about my second question?


2011/3/29 Sheng Chen <chensheng2010@gmail.com>

> I use 'nodetool compact' command to start a compaction.
> I can understand that extra disk spaces are required during the compaction,
> but after the compaction, the extra spaces are not released.
>
> Before compaction:
> SSTable count: 10
> space used (live): 19G
> space used (total): 21G
>
> After compaction:
> sstable count: 1
> space used (live): 19G
> space used (total): 42G
>
>
> BTW, given that compaction requires double disk spaces, does it mean that I
> should never reach half of my total disk space?
> e.g. if I have 505GB data on 1TB disk, I cannot even delete any data at
> all.
>
>
>
>
>

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>From a previous thread of the same topic, I used a force GC and the extra s=
paces are released.<div><br></div><div>What about my second question?</div>=
<div><br></div><div><br><div><br><br><div class=3D"gmail_quote">2011/3/29 S=
heng Chen <span dir=3D"ltr">&lt;<a href=3D"mailto:chensheng2010@gmail.com">=
chensheng2010@gmail.com</a>&gt;</span><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex;">I use &#39;nodetool compact&#39; command to=
 start a compaction.=A0<div>I can understand that extra disk spaces are req=
uired during the compaction, but after the compaction, the extra spaces are=
 not released.</div>
<div><br></div>
<div>Before compaction:</div><div>SSTable count: 10</div><div>space used (l=
ive): 19G</div><div>space used (total): 21G</div><div><br></div><div>After =
compaction:</div><div>sstable count: 1</div><div><div>space used (live): 19=
G</div>

<div>space used (total): 42G</div></div><div><br></div><div><br></div><div>=
BTW, given that compaction requires double disk spaces, does it mean that I=
 should never reach half of my total disk space?</div><div>e.g. if I have 5=
05GB data on 1TB disk, I cannot even delete any data at all.</div>

<div><br></div><div><br></div><div><br></div><div><br></div>
</blockquote></div><br></div></div>

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