If you are not familiar with Azure SQL Server Database’s Hyperscale tier, you can read previous posts (Azure SQL Database Hyperscale Tier and Azure SQL Hyperscale Tier – Next Milestone) to get an understanding of it. We had a use case today whereby upgraded our existing Azure SQL database from Premium tier to Hyperscale tier and thought to share our experience with the upgrade.
Before the update, we were aware that it would be one way upgrade and can’t be rolled back to any other tier once we are in Hyperscale tier. This is kind of consent that Microsoft also asks you to give by selecting the checkbox on portal screen during the upgrade process and we witnessed this after the upgrade –
You can see that we are in Hyperscale tier and all other tiers becomes greyed, marked as Not available.
Further, the upgrade was quite smooth with NO hiccups at all –
Upgrade time depends on the size of your existing database. Our database was about 300 gigs in actual size and it took about 40 minutes to get transitioned to hyperscale tier.
Immediately after this, we started running our existing workload to check if there is anything that might break. Though we were not anticipating anything to break down as it was merely an upgrade from DTU model to vCore based model with a different architecture but still we wanted to test this…and this all worked fine with no surprises. No impact at all.
Soon after, we started observing the performance and noticed a little better with this tier but not significant for our workload. By and large it was more aligned with Premium tier 125 DTUs equivalent to 2 vCores in core based model that is being suggested by Microsoft on generic grounds.
However, there was a nice observation around the cost…while Premium tier gives you Read Scale Out replica of your database free of cost, this Hyperscale tier charge you separately for it –
We thought to check if core based model charge you separately for replicas throughout or it is just this Hyperscale tier. It was discovered that only hyperscale tier charge you separately for the secondary read scale out replicas. Premium tier in DTU based model and the corresponding Business Critical tier in core based model both gives you an option of read scale out replicas and both gives you this free as shown in the snapshot below too –
Also, we tried scaling up from 2 vCores to 4 vCores which took less than 2 minutes. Since it’s independent of storage here so it was scaled up quickly.
So, we can say that so far so good and will update this post in future as we discover anything further worth to be shared.