How to clean up NextCloud stale locked files
Sometimes, due to connectivity issues (or even NextCloud bugs), files may end up in a locked state on the server. This means they can no longer be modified in any way, not even deleted.
How to monitor progress of a dd operation
By default dd doesn’t display any status information while performing its operation. Newer versions include a status parameter which can be used to activate progress output.
How to pre-configure Raspberry PI for remote SSH and Wifi
Many Raspberry PI projects are used headless (with no display device attached or if a display device exists, it’s not connected to the default HDMI or analog outputs).
In these instances it’s time consuming to connect the PI to a monitor and keyboard just to configure remote SSH access and wireless connection details (and in rare occasions it may even not be possible).
Luckily, the good folk developing Raspbian implemented shortcuts and workarounds that allow things to be pre-configured even before booting the PI.
How to backup hard disk removed from RAID volume
After migrating a RAID volume to new disks it’s handy to keep a full partition backup around.
For this we can use partclone, a handy smart backup utility which is capable of recognizing multiple filesystem structures and then save only used data.
How to adjust TLER value on hard disk (for data recovery)
In case the hard disk itself is taking too long to respond, some operations will fail and can cause the controller (software or hardware) to drop the disk out of the RAID.
Even when no RAID is used, the hard disk itself can still spend too much time retrying a (failing) read, causing unwanted delays and possible further damage.
To alleviate this, you can try to use a feature called TLER (Time Limited Error Recovery) or CCTL (Command Completion Time Limit).
How to install CentOS remotely using VNC
Installing an operating system remotely comes handy when you don’t want to spend all the time required for the install process next to the physical machine or want to give someone else access to perform the procedure.
CentOS is one of the OSes which supports remote installation using the VNC protocol.
Keeping SSH connections alive
By default SSHd will terminate an ongoing connection if there was no traffic (incoming or outgoing) for a while.
If you usually leave remote sessions running for long amounts of time and hate the unexpected disconnects, this can be changed by enabling the keep-alive feature on the server directly so it applies to all remote sessions regardless of client used.
Migrating CentOS 7 to PHP 7
CentOS is a conservative distribution giving you the most stability and security, at the expense of newer features like the latest PHP release.
Fortunately there are ways around for getting a newer PHP by using one of the several repositories out there providing updated packages. My personal choice for this task is Remi’s Repository.
Installing munin-node on OPNsense
Since OPNsense is more vanilla FreeBSD it is a lot simpler to install additional FreeBSD software on it than on pfSense.
One piece of additional software that can be useful, especially for monitoring and statistics purposes, is munin.
How to install OPNSense on PCEngines’ APU2
I have been looking for a good alternative which could handle my gigabit internet connection and I believe I made a good choice going with PCEngine’s APU2 embedded system.
I tried following various tutorials dedicated for installing both pfSense and OPNsense on this device, however they didn’t quite work on the APU (or in my case), so I tried a personal method which proved successful.
How to install Webmin on OPNSense
Webmin is not part of the OPNSense repository packages, however as OPNSense is more vanilla FreeBSD than pfSense it is relatively easy to install additional packages.
For compatibility and stability reasons the FreeBSD repository is disabled by default, but it can be enabled…
Configuring static IP address and virtual interfaces in Webmin
When assigning multiple IP addresses to a single server by using virtual interfaces on the same single main interface it is necessary to switch to a static IP configuration.
Doing network configuration remotely is a bit risky but with the correct sequence of steps it is possible to switch from DHCP to static IP without any downtime.