Articles in the system_administration category

  1. Introduction to DRBD

    Posted on in system_administration

    DRBD, which stands for Distributed Replicated Block Device, is a software-based, shared-nothing, replicated storage solution for mirroring the content of block devices (such as hard disks, partitions, logical volumes, etc.) between servers. It is often used to build high-availability (HA) clusters and is integrated into the Linux kernel, making it …

  2. FreeBSD TCP Performance Tuning

    Posted on in system_administration

    To enable RFC 1323 Window Scaling and increase the TCP window size to 1 MB on FreeBSD, add the following lines to /etc/sysctl.conf and reboot.

    net.inet.tcp.rfc1323=1  
    kern.ipc.maxsockbuf=16777216  
    net.inet.tcp.sendspace=1048576  
    net.inet.tcp.recvspace=1048576
    

    You can make these …

  3. Algorithms For TCP Congestion Control

    Posted on in system_administration

    Note: Although this is a continuation of the TCP Performance Tuning article series, it's also valuable as a standalone reference.

    This list includes a mix of both well-established and newer algorithms, reflecting the ongoing advancements in TCP congestion control research and deployment. Algorithms like CUBIC and BBR are particularly notable …

  4. Optimizing Website Performance: Benefits of Using Gzip with Nginx

    Posted on in system_administration

    In today's fast-paced digital landscape, website performance is paramount. Users demand speedy loading times, and search engines reward fast-loading websites with higher rankings. As a web server, Nginx is renowned for its performance and scalability, but to further enhance your web application's efficiency, it's vital to utilize techniques like Gzip …

  5. Using Memcached for PHP Session Storage

    Posted on in system_administration

    Effective session management is crucial for web applications to maintain user state and provide a seamless experience. PHP offers several session storage options, and one of the most efficient and scalable choices is Memcached. In this blog post, we'll explore how to use Memcached for PHP session storage, the benefits …

  6. OpenSSH: Using a Bastion Host

    Posted on in System Administration

    Quick and dirty OpenSSH configlet here. If you have a set of hosts or devices that require you to first jump through a bastion host, the following will allow you to run a single ssh command:

    Host *
        ProxyCommand ssh -A <bastion_host> nc %h %p
    

    Change the Host * line to best …

  7. Cache has broken packages, exiting

    Posted on in system_administration

    I've been getting the following error from cron.daily in my inbox lately:

    /etc/cron.daily/apt:
    Cache has broken packages, exiting
    

    That's an annoying email to get everyday. I decided I would apt-get clean and that would probably fix the problem:

    $ sudo apt-get clean
    $ sudo apt-get dist-upgrade
    Reading package …

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