44 votes
Accepted

CPU clock speed versus CPU core count - higher GHz, or more cores for SQL Server?

The general rule of thumb is keep the core count as low as possible, and the processor speed as high as possible. The licensing math on that proves the point at ~$7,500 USD per core for Enterprise ...
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  • 67k
16 votes
Accepted

Cluster design: if I expect to insert data into several tables every week, is it a bad idea to cluster them?

I have yet to see a real world user scenario where the benefit (saving a bit of disk or I/O or block access) of using a cluster instead of just regular tables (or IOTs) with joins is so significant ...
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  • 37.9k
14 votes

CPU clock speed versus CPU core count - higher GHz, or more cores for SQL Server?

Hold on hold on hold on While the performance and licensing aspects are interesting, they're not the only aspect of a workload to consider. One thing that can have an impact on processor choice is ...
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  • 33.4k
14 votes
Accepted

Can one of Windows failover cluster nodes run on Linux?

As SQL Server is available for Linux can I configure Clustering on Linux nodes? You can configure Corosync and pacemaker for Linux. Good luck. I mean mixed with Windows - some nodes are on Linux, ...
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13 votes
Accepted

How to restart MariaDB Galera cluster?

MariaDB Galera Cluster: Solution 1: 1) I've changed safe_to_bootstrap parameter to 1 on one of the node in the file /var/lib/mysql/grastate.dat: safe_to_bootstrap: 1 2) After that I killed all mysql ...
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  • 343
13 votes
Accepted

Does clustering provide disaster recovery in MS SQL Server?

By itself, no: clustering relies on shared storage. A failover cluster with shared storage looks like this: All 4 of the components - the 2 servers, the switch, and the shared storage - should be ...
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  • 41.3k
10 votes
Accepted

Are "Always On Failover Cluster Instances" and "SQL Server Failover Clustering" the same thing?

Yes it is the same thing. See section 3 which explains this term. First lets get few terms straight. Windows Server Failover Clustering A Windows Server Failover Clustering (WSFC) cluster is a ...
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  • 12.2k
10 votes

Cluster design: if I expect to insert data into several tables every week, is it a bad idea to cluster them?

caveat emptor Whenever you have a schema design idea, run benchmarks to (dis)prove its usefulness. For me, using a non-standard schema design needs to be proven to have a significant benefit prior to ...
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  • 4,693
9 votes

Availability Groups automatic failover is not so automatic

You have a quorum issue in this setup. There are only two participants in the cluster: SQL1 SQL2 If SQL1 goes down, there's no way for SQL2 to know that it should be the primary. For all SQL2 ...
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  • 27.1k
9 votes
Accepted

Why is there automatic failover for HA and manual failover for DR?

It is tricky with generalizations and simplifications. However, here's an attempt: My feeling is that HA generally is closer geographically. In such cases it is more realistic to use synchronous ...
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9 votes
Accepted

Availability Group - how much data was lost after forced failover

Go to SSMS Object Explorer Expand Always On High Availability Expand Availability Groups Right click your AG Select Show Dashboard In the dashboard, above the list of AG databases and their status, ...
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8 votes

Why is there automatic failover for HA and manual failover for DR?

This is going to change wildly based on each business's tolerance for data loss and recovery times. But, here are my thoughts on the matter. The SQL Servers do not live in a vacuum and our HA and DR ...
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7 votes

Restart the active node services without failover

Use the Failover Cluster Manager application to manually stop the services. This tells the cluster you are intentionally shutting down the service, so it won't attempt to bring it back up on another ...
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  • 67k
7 votes
Accepted

SQL Server Clustering - Active/Active or Active/Passive?

Active/Active refers, typically, to the idea of having multiple copies of a database available concurrently. However, in SQL Server, there is no way to accomplish that for read-write databases, other ...
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  • 67k
7 votes
Accepted

Availability Groups using Multi-Subnet Clustering: Preferred Owners for Roles and Possible Owners for AG Listener IPs

My question is this: should we change the default settings in the Failover Cluster Manager, specifically the Preferred Owners of the AG role and the Possible Owners of the AG listener IP resources? ...
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7 votes

Always On Failover Clustering vs Always On Availability Groups

To start with there is nothing called as Always On or Always ON availability groups it is simply called as Availability groups. Always On Clustering and Always On Availability Groups are 2 ...
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  • 18.2k
7 votes
Accepted

Availability Group cluster memory issue after network issues. How to dump HADR Log Block Msg Pool?

I have noticed after every WAN issue where the WAN connection is flapping, and the off site nodes constantly disconnect and reconnect, the memory of the primary server gets consumed by the "HADR Log ...
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7 votes

SQL Server Always On File Share Witness (Quorum vote) on different subnet to other nodes

Could someone confirm is having the file share server on a different subnet a big no no in an AlwaysOn environment? It's completely fine to have the FSW on a different subnet, there is absolutely ...
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7 votes
Accepted

Do I need "New SQL Server Failover Cluster installation" to run Availability groups with manual failover?

If you want to just use stand alone instances - which is the most common method of implementing availability groups [stand alone to stand alone] - then you only need to do a stand alone install. So, ...
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7 votes
Accepted

Why putting SQL Agent offline caused WSFC to fail over on passive node?

If you look in Failover Cluster Manager, if you select the role for the Failover Cluster Instance (FCI) Role, then select the "Resources" tab at the bottom you'll see that the role is ...
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  • 14.2k
6 votes
Accepted

Failover Cluster Diagnostic Logs

You can change this behavior with the ALTER SERVER CONFIGURATION statement. The flexibility to modify all of the necessary parameters (path, max files, max file size) should give you enough control ...
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6 votes

Three Node Cluster that Allows For Two Failures

If you want to be able to sustain a failover of two nodes within the failover cluster, then you'll need to ensure that you have five voters for quorum. You currently have three nodes, and even if you ...
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6 votes

Controlled shutdown/startup of a cluster

Shutting down the cluster for a move is pretty straight forward. Open the failover cluster administrator. Using the failover cluster administrator stop the resource groups for the SQL instances Shut ...
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  • 26.8k
6 votes
Accepted

Is MySQL Cluster a right choice?

When evaluating clustered solutions you need to think about the read/write profile of your application and match that against available solutions. For a heavy read based profile of an application, ...
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6 votes
Accepted

Are multiple databases sharding for read on docker as a good idea?

The gotcha with sharding is that the application has to know which shard to query. Generally, this is done by sharding on something like client. I'll adapt one of my old blog posts to use as my answer....
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  • 41.3k
6 votes

SQL Cluster with different Edition

I've never tried this but I'm reliably informed it is 100% not possible. It is certainly not supported by Microsoft, for good reason, so why would you do it? The SQL Server edition you are ...
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  • 1,714
6 votes
Accepted

Manual failover of AAG in SQL Server 2012

Do not use Failover Cluster Manager for your failovers. It can cause problems. Do not use the Failover Cluster Manager to move availability groups to different nodes or to fail over availability ...
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  • 5,766
6 votes
Accepted

Can a query whose execution plan uses parallelization use the cores of a processor on a another server that's part of the same Availability Group?

No, execution plan parallelization refers to using multiple cores on the server executing the query. Parallelize plans are not executed across availability group replicas.
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  • 161
6 votes

SQL Server: Multiple Availability Groups, one cluster, how do I keep the primary cluster node as primary?

Converted from comments: Are you referring to the core cluster resources? If yes, the answer is no, failover of the cluster role for the availability group would not impact the core cluster ...
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6 votes

Why do I need witness in WSFC with two nodes?

Straight from the docs, with a two-node cluster without a witness: One node's vote is zeroed, so the majority vote is determined out of a total of 1 vote. If the non-voting node goes down ...
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