45 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 ...
Hannah Vernon's user avatar
  • 70k
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 ...
Balazs Papp's user avatar
  • 40.7k
15 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 ...
Erik Darling's user avatar
  • 40.8k
14 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 ...
Oleksandr's user avatar
  • 383
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, ...
Sean Gallardy's user avatar
12 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 ...
Brent Ozar's user avatar
11 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 ...
SqlWorldWide's user avatar
  • 13.2k
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 ...
Michael Kutz's user avatar
  • 4,829
10 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 ...
Tibor Karaszi's user avatar
10 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, ...
Aleksey Vitsko's user avatar
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 ...
Josh Darnell's user avatar
  • 29.2k
8 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 ...
Hannah Vernon's user avatar
  • 70k
8 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 ...
Hannah Vernon's user avatar
  • 70k
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 ...
Jonathan Fite's user avatar
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? ...
Sean Gallardy's user avatar
7 votes
Accepted

Alternative to CLUSTER without table lock

If it's just about table bloat, VACUUM FULL is the tool to do it. (VACUUM only shrinks the physical file if it can opportunistically truncate it at the end.) However, VACUUM FULL also takes an ...
Erwin Brandstetter's user avatar
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 ...
Shanky's user avatar
  • 19k
7 votes

Why am I unable to create this Availability Group? (error 35220)

Here's the blog where I found the answer: https://bahtisametcoban.home.blog/2019/01/04/always-on-availability-groups-with-multi-subnet-failover-cluster/. In case you don't feel like reading through ...
RollingDBA's user avatar
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 ...
Sean Gallardy's user avatar
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 ...
Sean Gallardy's user avatar
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, ...
Sean Gallardy's user avatar
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 ...
AMtwo's user avatar
  • 16.1k
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, ...
Lee Parayno's user avatar
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....
Brent Ozar's user avatar
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 ...
Molenpad's user avatar
  • 1,784
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 ...
Tara Kizer's user avatar
  • 5,956
6 votes

AlwaysOn AG versus FCI

In general, FCI is more beneficial compared to AG because of various reasons already mentioned above. Of course, 2-node FCI is completely great but should not be built on top of storage spaces direct ...
Net Runner's user avatar
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.
addp009's user avatar
  • 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 ...
mv  ٠〳comment  ٠〳answer's user avatar
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 ...
David Browne - Microsoft's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible