When running Oracle databases under Linux, some additional kernel parameters need to be set. Oracle lists these parameters in the appopriate documentation - e.g. for the most recent version 12c: [click me!]

Especially for Enterprise Linux 7 there is a dedicated profile for the tuned service (RPM package …

Yesterday Red Hat released the 8th update of Red Hat Enterprise Linux 6. The changes have been documented in the release and technical notes:

• Release Notes: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/6.8_Release_Notes/index.html
• Technical Notes: …

Recently I had issues with configuring CardDAV-Sync and CalDAV-Sync along with Owncloud after a fresh Android installation. Specifying the well-known URLs just produced several error messages inside the app:

https://my-server.tld/owncloud/remote.php/caldav/principals/USER/ …

As preparation for a restore test, I removed the master boot record (MBR) of a Linux system recently:

1# dd if=/dev/zero of=/dev/sda bs=512 count=1

This command fills the first 512 bytes (containing the partition table and bootloader) of the first hard drive (/dev/sda) with zeroes (/dev/zero).

The problem is when you …

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If a host has …

Sometimes it happens that you lock out yourself from your Linux system. In the worst case, additional security concepts or conditions might hamper access to the system, for example:

• No root access
• System cannot be rebooted to reset the password in a chroot session
• No colleague with system access available

Recently I …

During the installation of kernel updates I stumbled upon a cramped /boot partition recently. Solving this issue is quite easy - e.g. it is possible to manually dig through the RPM database, exclude the running kernel and remove all other packages. Anyhow, this is neither comfortable nor elegant:

1# yum remove `rpm …

Since 2008 I have been using the free Linux distribution IPCop to implement a customized firewall/a router. Of course, DSL providers also equip their customers with routers, but back then I was missing a couple of functions. To name some of them:

• IPSec / OpenVPN
• NTP time server
• DMZ segmentation
• WLAN access point with …