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From Andrew <redmu...@gmail.com>
Subject Re: Backup Cassandra to
Date Thu, 12 Jun 2014 17:27:18 GMT
There isn’t a lot of “actual documentation” on the act of backing up, but I did research
for my own company into the act of backing up and unfortunately, you’re not going to have
a similar setup as Oracle.  There are reasons for this, however.

If you have more than one replica of the data, that means each node in the cluster will likely
be holding it’s own unique set of data.  So you would need to back up the ENTIRE set of
nodes in order to get an accurate snapshot.  Likewise, you would need to restore it to the
cluster of the same size in order to restore it (and then run refresh to tell Cassandra to
reload the tables from disk).

Copying the snapshots is easy—it’s just a bunch of files in your data directory.  It’s
even smaller if you use incremental snapshots.  I’ll admit, I’m no expert on tape drives,
but I’d imagine it’s as easy as copy/pasting the snapshots to the drive (or whatever the
equivalent tape drive operation is).

What you (and I, admittedly) would really like to see is a way to back up all the logical
*data*, and then simply replay it.  This is possible on Oracle because it’s typically restricted
to either one (plus maybe one or two standbys) that don’t “share” any data.  What you
could do, in theory, is literally select all the data in the entire cluster and simply dump
it to a file—but this could take hours, days, or even weeks to complete, depending on the
size of your data, and then simply re-load it.  This is probably not a great solution, but
hey—maybe it will work for you.

Netflix (thankfully) has posted a lot of their operational observations and what not, including
their utility Priam.  In their documentation, they include some overviews of what they use: https://github.com/Netflix/Priam/wiki/Backups

Hope this helps!

Andrew

On June 12, 2014 at 6:18:57 AM, Jack Krupansky (jack@basetechnology.com) wrote:

The doc for backing up – and restoring – Cassandra is here:
http://www.datastax.com/documentation/cassandra/2.0/cassandra/operations/ops_backup_restore_c.html
 
That doesn’t tell you how to move the “snapshot” to or from tape, but a snapshot is
the starting point for backing up Cassandra.
 
-- Jack Krupansky
 
From: Camacho, Maria (NSN - FI/Espoo)
Sent: Thursday, June 12, 2014 4:57 AM
To: user@cassandra.apache.org
Subject: Backup Cassandra to
 
Hi there,
 
I'm trying to find information/instructions about backing up and restoring a Cassandra DB
to and from a tape unit.
 
I was hopping someone in this forum could help me with this since I could not find anything
useful in Google :(
 
Thanks in advance,
Maria
 


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