Category Archives: Storage

#DRBD: Synchronization of sites after the failed DR (disaster recovery) site is recovered

By | April 24, 2017

This is a follow-up tutorial on the DRBD replication posts about resynchronization of sites after the failed DR site is recovered. More than a year ago I described in a long tutorial how to use DRBD in a real production environment and the challenges associated to it. See: DRBD based disk replication of a production… Read More »

#DRBD: Resynchronization of sites after the failed PR site is recovered (DRBD split brain recovery)

By | March 6, 2017

This is a follow-up tutorial on the DRBD replication posts about resynchronization of sites after the failed PR site is recovered (DRBD split brain recovery). More than a year ago I described in a long tutorial how to use DRBD in a real production environment and the challenges associated to it. See: DRBD based disk… Read More »

#DRBD: Promoting the DR site as the main site when PR is failed

By | March 6, 2017

This is a follow up tutorial on the DRBD replication posts about promoting the DR site as the main site when PR is failed. More than a year ago I described in a long tutorial how to use DRBD in a real production environment and the challenges associated to it. See: DRBD based disk replication… Read More »

#DRBD: Gracious role switching of live sites configured with DRBD replication

By | March 6, 2017

This is a follow up tutorial on the DRBD replication posts about gracious role switching of live sites configured with DRBD replication. More than a year ago I described in a long tutorial how to use DRBD in a real production environment and the challenges associated to it. See: DRBD based disk replication of a… 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 »

Migrate Windows 10 to SSD

By | January 25, 2016

My desktop Dell XPS 8700 is a beast even after more than 2 years of the official release. The problem with it is that in a typical big corporate fashion it contains an unbalanced set of hardware: * A very fast processor * 16GB of memory (4x4GB so not so up-gradable to the 32GB maximum)… 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 »