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From <>
Subject RE: Removal of old data files
Date Fri, 02 Sep 2011 13:01:23 GMT
I see. Thank you for helpful information 


-----Original Message-----
From: Sylvain Lebresne [] 
Sent: Friday, September 02, 2011 3:40 AM
Subject: Re: Removal of old data files

On Fri, Sep 2, 2011 at 12:11 AM,  <> wrote:
> Yes, I see files with name like
>     Orders-g-6517-Compacted
> However, all of those file have a size of 0.
> Starting from Monday to Thurseday we have 5642 files for -Data.db, 
> -Filter.db and Statistics.db and only 128 -Compacted files.
> and all of -Compacted file has size of 0.
> Is this normal, or we are doing something wrong?

You are not doing something wrong. The -Compacted files are just marker, to indicate that
the -Data file corresponding (with the same number) are, in fact, compacted and will eventually
be removed. So those files will always have a size of 0.


> yuki
> ________________________________
> From: aaron morton []
> Sent: Thursday, August 25, 2011 6:13 PM
> To:
> Subject: Re: Removal of old data files
> If cassandra does not have enough disk space to create a new file it 
> will provoke a JVM GC which should result in compacted SStables that 
> are no longer needed been deleted. Otherwise they are deleted at some 
> time in the future.
> Compacted SSTables have a file written out with a "compacted" extension.
> Do you see compacted sstables in the data directory?
> Cheers.
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> On 26/08/2011, at 2:29 AM, yuki watanabe wrote:
> We are using Cassandra 0.8.0 with 8 node ring and only one CF.
> Every column has TTL of 86400 (24 hours). we also set 'GC grace 
> second' to 43200
> (12 hours).  We have to store massive amount of data for one day now 
> and eventually for five days if we get more disk space.
> Even for one day, we do run out disk space in a busy day.
> We run nodetool compact command at night or as necessary then we run 
> GC from jconsole. We observed that  GC did remove files but not 
> necessarily oldest ones.
> Data files from more than 36 hours ago and quite often three days ago 
> are still there.
> Does this behavior expected or we need adjust some other parameters?
> Yuki Watanabe
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