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From Jeff Jirsa <>
Subject Re: Hiper-V snapshot and Cassandra
Date Tue, 20 Oct 2015 15:52:23 GMT
As long as your hyper-v/vss snapshots include both the data directory and the commit log directory,
then they’re exactly as good as tolerating a single power outage – you should be able
to load the sstables and replay  commit log and be fine. 

Assuming you’re moving the hyper-v/vss snapshot to another host (using DPM or similar),
it’s probably going to work the way you expect.

You’ll note, however, the cassandra was designed to do the opposite of what you’re doing
– rather than having one monolithic database that’s scaled up, the canonical use case
for cassandra is to have a number of smaller databases, so you still get the same capacity
and throughput, but you also get high availability and fault tolerance. It may be worth noting
(as Mr. Coli suggested) that you’re using cassandra in an atypical fashion, and if you add
more smaller nodes, then you’ll gain performance, gain HA, gain capacity, and that moving
snapshots will be faster because there’s less data per system.

From:  Raul D'Opazo
Reply-To:  ""
Date:  Tuesday, October 20, 2015 at 4:22 AM
To:  ""
Subject:  Hiper-V snapshot and Cassandra


I am really new with Cassandra and i have some questions regarding the backup of Cassandra
with TB of info. So please, forgive me if I ask a noob question. 

I only have one node, in one server (Windows 2012), and Cassandra will grow up to 4TB approx.
It is a hiper-v virtual machine, with enough resources.

I have done snapshots and it is ok, because we don’t double the size in each snapshot, but
I need to have other solution in case of disks problems. 

Copying these snapshots using other backup systems is crazy, approx.. 500MB/s it will last

I am thinking if hiper-v virtual machine snapshots can be used to recover Cassandra in a consistence
way. Is it possible?

This will avoid me to copy snapshots to other network location or backup system.




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