Sometimes it happens that vagrant hangs during boot of your virtual image. Right after typing: bash $ vagrant up It hangs for a long time and then finally throws: bash [default...

boot grub kernel linux vagrant virtualbox

Unfortunately the Linux DNS resolver has no direct support for detecting and doing failovers for DNS servers. It keeps feeding requests to your primary resolving nameserver, waits...

bash campfire crontab dns linux nameserver papertrail redundancy spof

I recently had an annoying encounter with the error message: Too many authentication failures for root. I found out this can be caused because you've hoarded too many SSH keys :)...

linux security ssh

If something weird is happening, you want to know everything that's going on on a server, as fast as possible. At these times, you will be very happy to have a simple alias wtf in...

bash debugging linux server tail wtf

> "Simplicity is prerequisite for reliability." Edsger W. Dijkstra As our experience grows, we learn from past mistakes and discover what's truely important in relia...

devshm io linux memcache pecl performance php ram tmpfs

With SSH you can securely login to any Linux server and execute commands remotely. You can even use SSH to transfer and synchronize files from one server to another. Automating the...

linux ssh

Synchronizing files from one server to another is quite awesome. You can use it for backups, for keeping web servers in sync, and much more. It's fast and it doesn't take up as muc...

backup crontab linux rsync ssh synchronization

Deleting a file or reformatting a disk does not destroy your sensitive data. The data can easily be undeleted. That's a good thing if you accidentally throw something away, but wha...

linux security

Recently two of my articles reached the Digg frontpage at the same day. My web server isn't state of the art and it had to handle gigantic amounts of traffic. But still it served p...

apache caching io linux mysql pear performance php

CDs and DVDs don't have the eternal life, so you might want to back them up as ISO images. All the files and properties of the original disc, stored in a single file. You can also...

dd iso linux

If you've got a website that's heavy on your web server, you might want to run some processes like generating thumbnails or enriching data in the background. This way it can not in...

crontab linux

Since 2005 there has been an immense increase in brute force SSH attacks and though Linux is pretty secure by default, it does not stop evil programs from indefinitely trying to lo...

firewall iptables linux security ssh ubuntu

Everyone knows that RAM is so much faster than a hard disk. To illustrate, while a current SATA disk has peak transfer rates of 375 MB/s, current RAM can do a mind blowing 12,500 M...

apache devshm io linux performance pxe ram sata tmpfs ubuntu umask

Ever wanted to change the crontab of a server, but got an editor on screen that you're totally unfamiliar with? There are a lot of causes for this annoyance, but one is that somebo...

bash editor linux mc pico vim

I recently had to install a couple of squid servers to act as reverse proxies for a webcluster. You can teach the squid server to stand in between in the end users and the webserve...

cat comments config linux squid