This blog post shows you how NTFS stores data, what the NTFS Allocation Unit means, and how SQL Server performs IOs of variable size. How NTFS Stores Data on Disk A Master File Table (MFT) is the data structure that describes files and directories on NTFS. In Figure 1, you can see an MTF record has several sections describing the metadata about the file and pointers to blocks that make up the file.
This post is a reference post for retrieving IO statistics for data and log files in SQL Server. We’ll look at where we can find IO statistics in SQL Server, query it to produce meaningful metrics, and discuss some key points when interpreting this data. The Source DMF The primary source for file latency data is the dynamic management function sys.dm_io_virtual_file_stats. The data in this DMF is per file. The query below joins with sys.
Limits in Containers Docker gives you the ability to control a container’s access to CPU, Memory, and network and disk IO using resource constraints, sometimes called Limits. You define limits as parameters when creating containers. In its default configuration, a container will have no resource constraints for accessing resources of the host operating system. This post will look at how to configure resource constraints in Docker and look at how SQL Server sees the resources when CPU and Memory resource constraints are in place.
People often ask me what’s the number one thing to look out for when running SQL Server on Kubernetes…the answer is memory settings. In this post, we’re going to dig into why you need to configure resource limits in your SQL Server’s Pod Spec when running SQL Server workloads in Kubernetes. I’m running these demos in Azure Kubernetes Service (AKS), but these concepts apply to any SQL Server environment running in Kubernetes.
When working with SQL Server in containers and Kubernetes storage is a key concept. In this post, we’re going to walk through how to deploy SQL Server in Kubernetes with Persistent Volumes for the system and user databases. One of the key principals of Kubernetes is the ephemerality of Pods. No Pod is every redeployed, a completely new Pod is created. If a Pod dies, for whatever reason, a new Pod is created in its place there is no continuity in the state of that Pod.
In this blog post we’re going to revisit how SQL Server on Linux responds to external memory pressure. This is a very long post, and it ends with me not knowing exactly what’s going on…but the journey is pretty fun…let’s go! On Windows-based SQL Server systems we’ve become accustomed to the OS signaling to SQL Server that there’s a memory shortage. When signaled, SQL Server will kindly start shrinking it’s memory caches, including the buffer pool, to maintain overall system stability and usability.
In this blog post we’re going to explore how SQL Server on Linux responds to external memory pressure. On Windows based SQL Server systems we’ve become accustomed to the OS signaling to SQL Server that there’s a memory shortage. When signaled, SQL Server will kindly start shrinking it’s memory caches, including the buffer pool, to maintain overall system stability and usability. We’ll that story is a little different in SQL Server on Linux…let’s look and see how SQL Server on Linux responds to external memory pressure
I’m very pleased to announce that I will be speaking at PASS Summit 2017! This is my first time speaking at PASS Summit and I’m very excited to be doing so! What’s more, is I get to help blaze new ground on a emerging technology SQL Server on Linux! My session is “Monitoring Linux Performance for the SQL Server Admin” so if you’re a Windows or SQL Server administrator, this session is for you.
With SQL Server on Linux, Microsoft has recognized that they’re opening up their products to a new set of users. People that aren’t used to Windows and it’s tools. In the Linux world we have a set of tools that work with our system performance data and present that to us as text. Specifically, the placeholder for nearly all of the Linux kernel’s performance and configuration data is the /proc virtual file system, procfs.
SQL 2014 Service Pack 2 was recently released by Microsoft and there is a ton of great new features and enhancements in this release.This isn’t just a collection of bug fixes…there’s some serious value in this Service Pack. Check out the full list here. One of the key things added in this Service Pack is an enhancement of the Extended Events for AlwaysOn Availability Group replication. Why are the new Availability Group Extended Event interesting?