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From S C <as...@outlook.com>
Subject RE: Question on Cassandra Snapshot
Date Tue, 19 Feb 2013 20:35:33 GMT
Thank you Aaron.

From: aaron@thelastpickle.com
Subject: Re: Question on Cassandra Snapshot
Date: Mon, 18 Feb 2013 06:37:34 +1300
To: user@cassandra.apache.org

With incremental_backup turned OFF in Cassandra.yaml - Are all SSTables are under /data/TestKeySpace/ColumnFamily
at all times?No. They are deleted when they are compacted and no internal operations are referencing
them. 
With incremental_backup turned ON in cassandra.yaml - Are current SSTables under /data/TestKeySpace/ColumnFamily/
with a hardlink to /data/TestKeySpace/ColumnFamily/backups? Yes, sort of. *All* SSTables ever
created are in the backups directory. Not just the ones currently "live".
Lets say I have taken snapshot and moved the /data/TestKeySpace/ColumnFamily/snapshots/<snapshot-name>/*.db
to tape, at what point should I be backing up *.db files from /data/TestKeySpace/ColumnFamily/backups
directory. Also, should I be deleting the *.db files whose inode matches with the files in
the snapshot? Is that a correct approach? Backup all files in the snapshots. There may be
non .db extensions files if you use levelled compactionsWhen you are finished with the snapshot
delete it. If the inode is not longer referenced from the live data dir it will be deleted.

I noticed /data/TestKeySpace/ColumnFamily/snapshots/<timestamp>-ColumnFamily/ what are
these <timestamp> directories?Probably automatic snapshot from dropping KS or CF's
Cheers

-----------------Aaron MortonFreelance Cassandra DeveloperNew Zealand
@aaronmortonhttp://www.thelastpickle.com



On 16/02/2013, at 4:41 AM, S C <asf11@outlook.com> wrote:I appreciate any advise or
pointers on this.
Thanks in advance.

From: asf11@outlook.com
To: user@cassandra.apache.org
Subject: Question on Cassandra Snapshot
Date: Thu, 14 Feb 2013 20:47:14 -0600

I have been looking at incremental backups and snapshots. I have done some experimentation
but could not come to a conclusion. Can somebody please help me understanding it right?
/data is my data partition
With incremental_backup turned OFF in Cassandra.yaml - Are all SSTables are under /data/TestKeySpace/ColumnFamily
at all times?With incremental_backup turned ON in cassandra.yaml - Are current SSTables under
/data/TestKeySpace/ColumnFamily/ with a hardlink to /data/TestKeySpace/ColumnFamily/backups?
Lets say I have taken snapshot and moved the /data/TestKeySpace/ColumnFamily/snapshots/<snapshot-name>/*.db
to tape, at what point should I be backing up *.db files from /data/TestKeySpace/ColumnFamily/backups
directory. Also, should I be deleting the *.db files whose inode matches with the files in
the snapshot? Is that a correct approach? I noticed /data/TestKeySpace/ColumnFamily/snapshots/<timestamp>-ColumnFamily/
what are these <timestamp> directories?
Thanks in advance. SC
 		 	   		  
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