If running XenServer on a RAID array with writeback (controller cache) enabled and no battery backup, don’t lose power. If you do, you will discover the state.db is corrupt and XAPI fails to start. Everything is down, Dom0 lost it’s network config, you’re screwed. Maybe. This tutorial assumes you’ve got a metadata backup, all your […]
This is the preferred, Composer method for upgrading Magento 2.X.X between minor versions. Replace X.X with the minor version numbers of the target version. The last line is optional, use it only if you’re in the middle of a migration and need to continue to be able to sync data with a 1.x site. If […]
In a search to replace several NetGear WNCE2001 devices which had over time, proven themselves to be so unreliable they would literally kill entire wireless AND wired networks by randomly hijacking DHCP. I tried many devices — some either couldn’t bridge at all, others ‘worked’ but had such terrible range or connection quality they were […]
One-liner recursive grep + sed search and replace for php or other file types: grep “subject” * -rl –include=*.php | xargs sed -i -e ‘s/subject/replacement/g’
This reg key will enable the ability to boot from MegaRAID storage devices using the megasys2.sys driver. Useful to run before hand when upgrading or otherwise changing hardware to something with a LSI 9260, 9271 or similar card. This reg key REQUIRES that you already have the correct megasas2.sys driver installed one way or another. […]
Recently I upgraded my remote office connection to 100Mbps (cable) and spent almost a month dealing with slow downloads over an openVPN client connection. Uploads were fine (maxing out the pipe) but downloads were 12-20 Mbps at best and fluctuating like crazy. TCP client mode actually performed better than UDP so I knew something was […]
I cooked up a Munin plugin for my Surfboard 6141 which monitors ALL available data from the status page. If you’re having intermittant signal issues and want to keep detailed data for cable technicians, this is for you! Check it out on Github: https://github.com/djamps/munin-surfboard6141
After facing issue after issue with Idera/R1soft’s PXE and CD-ROM boot media — specifically, ancient kernels which are unable to obtain network connectivity on modern hardware, I decided to roll my own PXE boot image including the R1soft agent and a few other tools with the latest Debian stable. It turned out to be easier […]
On a new XenServer deployment EXT storage is default. Although EXT is nice (ability to manipulate raw VHD files and use sparse storage), LVM is faster and more stable. Here is how to switch between storage modes (be sure to back up all data first, as this will wipe everything in the repo): Use ‘xe […]
From time to time the du command doesn’t match up with df. This is due to deleted files that are still held open by a process. You can total the deleted but ‘still open’ file usage: lsof | awk ‘/deleted/ {sum+=$7} END {print sum}’ Or, to simply list all the files and their processes: lsof […]