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Performance of virtual storage (part 2) : QEMU

Virtualization Linux Sysadmin

In a previous blog post, I evaluated the performance penalty of virtual storage. I compared different host filesystems and different hypervisors (including QEMU). The conclusion was pretty harsh: in all tested configurations, virtual disks are almost 10 times slower than host drives. In this blog post, I will test additional QEMU configuration options, to see if I can get better results...

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Performance penalty of storage virtualization

Virtualization Linux

In a previous blog post, I showed how to use sysbench to benchmark a Linux system. I ran the tool on various systems I had access to, and I was staggered by the performance penalty of virtual storage: a virtual disk (vdi) is roughly 10 times slower than the actual disk it is reading from or writing to. In this blog post, I want to show the results of some additional tests that, sadly enough, will only confirm this observation...

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Virtual Machine Manager : the graphical interface for QEMU

Virtualization Linux

When discussing desktop hypervisors, one usually think to the main commercial players: VMware Workstation, VMware Fusion (for Mac), Hyper-V (built-in Windows) and VirtualBox. Actually, on Linux QEMU/KVM is also a solution thanks to the Virtual Machine Manager.

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Linux kernel threads and processes management : task_struct

Linux

In a previous blog post, I have shown how to create a Linux kernel module. This time I will show how the Linux kernel uses a task_struct to manage threads and processes. To illustrate, I will show how a kernel module can access and alter these, and thus also alter the inner working of the Linux kernel.

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Create a Linux kernel module

Linux Sysadmin

In a previous blog post, I presented how to build your own Linux kernel. This time I will show how to create, compile and load a very simple kernel module...

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Compile and install the Linux kernel

Linux Sysadmin

In this blog post I will show how to configure, compile and install a custom Linux kernel.

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Get started with Laravel Sail

Laravel PHP Docker

Running an complete Laravel development environment requires multiple services: web server, database server, queue worker etc. Laravel Sail helps you install and use all these using docker containers. Here is how to use it...

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Systemd : Basic concepts

Linux Sysadmin

Systemd is now the defacto standard init process on Linux systems. It is responsible for starting all required services... In this blog post we will present the basic concepts of systemd : basic usage, units and dependencies.

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Use docker-compose to create a dev environment for Laravel 6, 7 and 8

Laravel Docker PHP

Setting up a Laravel environment requires to install and configure multiple components: the correct PHP version, of course, but also a database, node server, probably queue worker and scheduler. To get you quickly started, here is how to deploy a dev environment for Laravel with docker compose.

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Add modules to your micro-Linux

Linux Sysadmin

In a previous blog post, we have built a micro-Linux system relying on initramfs. In this blog post, we will add modules to this minimal system.

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GitLab : fix "cgroups: cgroup mountpoint does not exist: unknown"

GitLab Sysadmin Docker

If you use GitLab pipelines to build Docker image, you may encounter the error "cgroups: cgroup mountpoint does not exist: unknown". Here is how to fix...

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Benchmark Linux systems with sysbench

Linux Sysadmin

In this blog post, I will show how to use sysbench to test the CPU, memory and storage performance of a Linux system. I also had the chance to access some diverse hardware (laptop, desktop, servers). So I'll also give some results for you to compare with.

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