Category Archives: Linux

Owncloud 8.1.5: File upload error Table ‘homeclouddb.oc_locks’ doesn’t exist”

By | February 9, 2017

After an OwnCloud upgrade I was getting complains from my users that WebDav and OwnCloud windows client were no longer able to upload files. By looking into owncloud.log the following was the repeated error: {“app”:”remote”,”message”:”An exception occurred while executing ‘SELECT * FROM `oc_locks` WHERE `userid` = ? AND (`created` + `timeout`) > 1456517102 AND ((… Read More »

Fedora Linux: Remove graphical mode boot and auto X start

By | February 18, 2016

On my servers I want to completely get read of graphical boot. I do not like fancy graphics that are not compatible with my basic Matrox integrated card and I do not want my system to start directly in X and load the server with unwanted stuff. STEP 1: Remove graphical boot Completely un-install the… Read More »

Fedora Linux: Boot a system from grub prompt

By | February 19, 2016

I had a situation when from a strange reason a default grub setup as a result of a system recovery was missing the lvm and raid modules so I was not able to boot. I have the following setup on the server: – my boot partition is in fact an ext4 partition over a mdraid… Read More »

Fedora Linux: Recover a corrupted system with a RAID1 boot partition with a lvm RAID1 root partition

By | February 19, 2016

There are times when even experimented sysadmins do stupid things. One of that moments happened to me when I tried some speed tests on my ssd RAID1. The result was not so satisfactory. Corrupted /boot partition with missing files and orphan inodes. To make things more complicated I have the following constraints that make this… Read More »

A+ Security for WordPress Blog – HTTP Strict Transport Security

By | February 9, 2017

Keeping the installation of your own WordPress blog highly secure is very important. In today’s fast pace discovery of security vulnerabilities you must keep an eye on all the new security threats and update as soon as possible the security to try to cover the new threat. An invaluable tool is the security test from… Read More »

RedHat/Fedora Linux NIC bonding

By | February 9, 2017

Red Hat Enterprise Linux allows administrators to bind multiple network interfaces together into a single channel using the bonding kernel module and a special network interface called a channel bonding interface. Channel bonding enables two or more network interfaces to act as one, simultaneously increasing the bandwidth and providing redundancy. The behaviour of the bonded… Read More »

#DRBD based disk replication of a production cluster to a remote site cluster on RHEL 6

By | May 26, 2017

1 General Considerations Our example enterprise applications run on a Linux Cluster with a shared cluster storage resource. Having this HA setup ensures that we have a high rate of service availability on the production site. To ensure that the disruption time in service of our enterprise application is minimal as possible the best solution… Read More »

iSCSI SAN resources configuration as shared disks in a cluster environment, replicated also with DRBD

By | April 24, 2017

The following configuration was created to use the iSCSI exported resources from a NetApp storage device as shared disk resources in a Linux cluster environment. The same resources are also replicated to a remote cluster using DRBD disk replication. The production environment contains four exported SAN resources which will be used as shared resources in… Read More »

Fedora Linux: LVM Single Drive to LVM RAID 1 Mirror Migration

By | March 3, 2017

All started when I wanted to have a true HA configuration for the server nodes. That implies that not only the storage of each server is a RAID10 setup, but also the boot and root resources are in a RAID1 configuration. I started to use an old and known tutorial to convert from standard installation… Read More »

Relax and Recover with bareos

By | June 30, 2015

A good way to backup the OS of the servers is to use rear Relax and Recover. Following are the steps to ensure that we have a proper rescue data set for both servers. STEP 1: Install rear from the Fedora repo on both nas1 and nas2 [root@nas1 ~]# dnf install rear [root@nas2 ~]# dnf… Read More »