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RavenDB 3.5 whirl wind tourCan you spare me a server?
One of the most important features in RavenDB is replication, and the ability to use a replica node to get high availability and load balancing across all nodes.
And yes, there are users who choose to run on a single instance, or want to have a hot backup, but not pay for an additional license because they don’t need the high availability mode.
Hence, RavenDB 3.5 will introduce the Hot Spare mode:
A hot spare is a RavenDB node that is available only as a replication target. It cannot be used for answering queries or talking with clients, but it will get all the data from your server and keep it safe.
If there is a failure of the main node , an admin can light up the hot spare, which will turn the hot spare license into a normal license for a period of 96 hours. At that point, the RavenDB server will behave normally as a standard server, clients will be able to failover to it, etc. After the 96 hours are up, it will revert back to hot spare mode, but the administrator will not be able to activate it again without purchasing another hot spare license.
The general idea is that this license is going to be significantly cheaper than a full RavenDB license, but provides a layer of protection for the application. We would still recommend that you’ll get for a full cluster, but for users that just want the reassurance that they can hit the breaker and switch, without going into the full cluster investment, that is a good first step.
We’ll announce pricing for this when we release 3.5.
More posts in "RavenDB 3.5 whirl wind tour" series:
- (25 May 2016) Got anything to declare, ya smuggler?
- (23 May 2016) I'm no longer conflicted about this
- (19 May 2016) What did you subscribe to again?
- (17 May 2016) See here, I got a contract, I say!
- (13 May 2016) Deeper insights to indexing
- (11 May 2016) Digging deep into the internals
- (09 May 2016) I'll have the 3+1 goodies to go, please
- (04 May 2016) I’ll find who is taking my I/O bandwidth and they SHALL pay
- (02 May 2016) You want all the data, you can’t handle all the data
- (29 Apr 2016) A large cluster goes into a bar and order N^2 drinks
- (27 Apr 2016) I’m the admin, and I got the POWER
- (25 Apr 2016) Can you spare me a server?
- (21 Apr 2016) Configuring once is best done after testing twice
- (19 Apr 2016) Is this a cluster in your pocket AND you are happy to see me?
Comments
I understand the desire to add the per-use charge, but if I was a sysadmin faced with a system issue, I now have the added stress of deciding whether I should try to fix our production server or switch to the hot spare knowing I'll have to explain myself to management to get another licence. Even worse would be someone else doing the above, but not bothering to renew the licence since I might not notice until crunch time.
Will there be a way to test the failover? I'm thinking you could allow up to 60 minutes without actually using up the one-time licence. That covers the problems above and also allows for some sort of routine failover testing.
(all written as a regular reader of this blog who doesn't use RavenDB)
1.There is an option to test the hot spare server without activating it, the test time is 60 minutes :) 2.You would know if your hot spare license was activated if you go to the hot spare part of manage your server, there you will see the activation time.
This is like you're selling hot spares as if they were "crystals" in a mobile game. Very very strange model.
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