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How to monitor SQLServer on Windows with Prometheus

Published: October 17, 2022 (Updated: June 26, 2024) in Telemetry, Database Performance, linux, sqlserver, prometheus by gary. Leave a Comment on How to monitor SQLServer on Windows with Prometheus.

TL;DR

Generate load on Microsoft SQLserver Windows from HammerDB on Linux

Published: October 14, 2022 (Updated: December 29, 2022) in Database Performance, tpc-c, hammerDB, linux, tpc, sqlserver by gary. Leave a Comment on Generate load on Microsoft SQLserver Windows from HammerDB on Linux.

Often it’s nice to be able to drive Windows applications and databases from Linux, especially if you are more comfortable in a Unix environment. This post will show you how to drive a Microsoft SQL Server database running on a Windows server from a remote Linux machine. In this example I am using Ubuntu 22.04, […]

QCOW 3 Ways

Published: September 13, 2022 (Updated: September 14, 2022) in Linux Virtualization by gary. Leave a Comment on QCOW 3 Ways.

How to mount QCOW images as Linux block devices tl;dr guestmount (requires libguestfs-tools) sudo guestmount -d <vm-name> –ro -i <mountpoint> qemu-nbd (requires the nbd driver) Load the kernel module modprobe nbd max_part=8 Bind the device to the image qemu-nbd –connect=/dev/nbd0 <vmdiskimage.qcow> Assuming partition #1 is the target mount /dev/ndb0p1 /a loopback mount. Requires converting qcow […]

Create a Linux VM with KVM in 6 easy steps

Published: September 10, 2022 (Updated: November 5, 2022) in Linux Virtualization, linux, virtualization, ubuntu, kvm, qemu by gary. 5 Comments on Create a Linux VM with KVM in 6 easy steps.

A Step-by-step guide to creating a Linux virtual machine on a Linux host with KVM,qemu,libvirt and ubuntu cloud images.

Using cloud-init with AHV command line

Published: August 26, 2022 (Updated: September 7, 2022) in AHV, linux, ahv by gary. Leave a Comment on Using cloud-init with AHV command line.

TL;DR Using cloud-init with AHV is conceptually identical to using KVM/QEMU- we need to use a few different tools with AHV You will need a Linux image that is configured to use cloud-init. A good source is cloud-images.ubuntu.com We will create a cloud-init textual file and create a mountable version using the cloud-localds tool on […]

Beware of tiny working-set-sizes when testing storage performance.

Published: July 1, 2022 (Updated: September 7, 2022) in Storage Performance, fio, nutanix, diskspd by gary. Leave a Comment on Beware of tiny working-set-sizes when testing storage performance..

I was recently asked to investigate why Nutanix storage was not as fast as a competing solution in a PoC environment. When I looked at the output from diskspd, the data didn’t quite make sense.

Comparing RDS and Nutanix Cluster performance with HammerDB

Published: June 14, 2022 (Updated: January 3, 2023) in Nutanix, hammerDB, nutanix, sqlserver, aws, rds by gary. Leave a Comment on Comparing RDS and Nutanix Cluster performance with HammerDB.

tl;dr In a recent experiment using Amazon RDS instance and a VM running in an on-prem Nutanix cluster, both using Skylake class processors with similar clock speeds and vCPU count. The SQLServer database on Nutanix delivered almost 2X the transaction rate as the same workload running on Amazon RDS. It turns out that migrating an […]

Single threaded DB performance on Nutanix HCI

Published: May 27, 2022 (Updated: January 3, 2023) in Nutanix, latency, windows, diskspd, aws, rds, sqlserver, fio by gary. 1 Comment on Single threaded DB performance on Nutanix HCI.

tl;dr A Nutanix cluster can persist a replicated write across two nodes in around 250 uSec which is critical for single-threaded DB write workloads. The performance compares very well with hosted cloud database instances using the same class of processor (db.r5.4xlarge in the figure below). The metrics below are for SQL insert transactions not the […]

AHV Tip: Shutdown multiple VMs in parallel

Published: May 6, 2022 (Updated: September 7, 2022) in AHV, acli, ahv by gary. Leave a Comment on AHV Tip: Shutdown multiple VMs in parallel.

Often in my lab I want to shutdown a large number of VMs quickly. In the example below I submit the power-off command for a maximum of 50 VMs in parallel. Be aware that we’re using the command line, and in line with true Unix philosophy the OS will assume we know what we are […]

AOS 6.1 Improvements for Day-2 database operations.

Published: March 8, 2022 (Updated: January 3, 2023) in Nutanix, nutanix, sqlserver, database, aos by gary. Leave a Comment on AOS 6.1 Improvements for Day-2 database operations..

AOS 6.1 greatly improved database performance on Nutanix especially when the guest VM uses just a single disk for all the database files. The underlying change is known as vdisk sharding. Basically it allows the Nutanix CVM to scale up the number of threads used to service a single virtual disk under heavy load.

[Guest Post] Why I became a performance engineer

Published: February 21, 2022 (Updated: January 3, 2023) in Miscellaneous by Dan Chilton. Leave a Comment on [Guest Post] Why I became a performance engineer.

First Off, I want to thank Gary for giving me an opportunity to be a guest writer on his blog, it’s an honor. My name is Dan Chilton and I have worked in technology for the past 20 years. As an introduction, today I just want to tell the story of why I became a […]

Nutanix Performance for Database Workloads

Published: November 24, 2021 (Updated: September 14, 2022) in Nutanix by gary. Leave a Comment on Nutanix Performance for Database Workloads.

We’ve come a long way, baby. Full disclosure. I have worked for Nutanix in the performance engineering group since 2013. My opinions are likely biased, but that also gives me a decent amount of context when it comes to the performance of Nutanix storage over time. We already have a lot of customers running database […]

How to generate a new hostid for a Cassandra node.

Published: July 21, 2021 (Updated: July 21, 2021) in Database Performance by gary. Leave a Comment on How to generate a new hostid for a Cassandra node..

If you clone a Cassandra VM with the goal of creating a cassandra cluster – you may find that every Cassandra node has the same hostID.

Using rwmixread and rate_iops in fio

Published: July 14, 2021 (Updated: December 29, 2022) in fio, fio by gary. 2 Comments on Using rwmixread and rate_iops in fio.

Creating a mixed read/write workload with fio can be a bit confusing. Assume we want to create a fixed rate workload of 100 IOPS split 70:30 between reads and writes. TL;DR Specify the rate directly with rate_iops=<read-rate>,<write-rate> do not try to use rwmixread with rate_iops. For the example above use. rate_iops=70,30 Additionally older versions of […]

Understanding fio norandommap and randrepeat parameters

Published: May 6, 2021 (Updated: December 29, 2022) in fio, fio by gary. 2 Comments on Understanding fio norandommap and randrepeat parameters.

The parameters norandommap and randrepeat significantly change the way that repeated random IO workloads will be executed, and also can meaningfully change the results of an experiment due to the way that caching works on most storage system.

How to drop tables for HammerDB TPC-C on SQL Server

Published: April 20, 2021 (Updated: January 3, 2023) in SQL Server, tpc-c, hammerDB, sqlserver by gary. Leave a Comment on How to drop tables for HammerDB TPC-C on SQL Server.

From the SQL Window of SQL*Server. Issue these commands to drop the tables and procedures created by HammerDB. This will allow you (for instance) to re-create the database, or create a new database with more warehouses (larger size) while retaining the same name/DB layout.