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From "Camacho, Maria (NSN - FI/Espoo)" <>
Subject RE: Backup Cassandra to
Date Fri, 13 Jun 2014 10:04:49 GMT
Thanks a lot for your responses.


From: ext Jabbar Azam []
Sent: Thursday, June 12, 2014 10:09 PM
Cc: Jack Krupansky
Subject: Re: Backup Cassandra to

Yes, I never thought of that.


Jabbar Azam

On 12 June 2014 19:45, Jeremy Jongsma <<>>
That will not necessarily scale, and I wouldn't recommend it - your "backup node" will need
as much disk space as an entire replica of the cluster data. For a cluster with a couple of
nodes that may be OK, for dozens of nodes, probably not. You also lose the ability to restore
individual nodes - the only way to replace a dead node is with a full repair.

On Thu, Jun 12, 2014 at 1:38 PM, Jabbar Azam <<>>
There is another way. You create a cassandra node in it's own datacentre, then any changes
going to the main cluster will be replicated to this node. You can backup from this node.
In the event of a disaster the data from both clusters and wiped and then replayed to the
individual node. The data will then be replicated to the main cluster.

This will also work for the case when the main cluster increases or decreases in size.


Jabbar Azam

On 12 June 2014 18:27, Andrew <<>>
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:

Hope this helps!


On June 12, 2014 at 6:18:57 AM, Jack Krupansky (<>)
The doc for backing up – and restoring – Cassandra is here:

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
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,

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