Addressing The Challenges of Upgrading to SQL Server 2012/2014
On last week’s webinar – “The Top 5 Challenges Upgrading to SQL Server 2012/2014 – and How to Overcome Them” – we had some great questions from the audience that we wanted to share more broadly. They touch on challenges around licensing, backward compatibility, and accessing cool new features such as read/write splt, replication-aware load balancing, and automatic failover.
Q: When you do synchronous replication with AlwaysOn, is write performance slower than with log-shipping?
A: Yes, but the typical user won’t be aware of it. You can see the exact latency in the data management views, but the UI won’t show it.
The larger issue has to do with when it’s practical to support synchronous replication. When the servers are all in one data center, it makes total sense to use synchronous replication. When servers span different data centers, as you’ll want to do for failover reasons, then it’s impractical to use synchronous replication because the write confirmation will take so long it’ll frustrate your users. So for all practical intents, you need to use asynchronous replication across data centers. For this reason, you need replication-aware load balancing so you’re never serving stale data from read-only servers.
Q: For these configurations with read/write split and load balancing, do you need multiple SQL Server licenses?
A: If you want the secondaries to be anything more than idle back-up servers, yes. If you want to use them for read load, for example, then they require a license.
Q: What is the benefit of using SQL in Azure [Microsoft’s cloud service] vs. on a virtual machine? SQL Azure has a much higher price point – is it worth it?
A: For the same compute/store/processing, cloud deployments are always more costly than on prem. What the cloud’s great for – Azure and any cloud – is handling bursty loads. When you have a temporary surge in traffic, it’s far more practical to handle that increased scale in the cloud than to build it on prem on a permanent basis.
Keep your questions coming! Send any technical questions you might have to info@scalearc.com and we’ll be glad to address them.
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