- What we know
- What we've created
- Hints and Kinks
- Checking Corosync cluster membership
- Configuring radosgw to behave like Amazon S3
- Downgrading to DRBD 8.3
- Fencing in Libvirt/KVM virtualized cluster nodes
- Fencing in VMware virtualized Pacemaker nodes
- GFS2 in Pacemaker (Debian/Ubuntu)
- Interleaving in Pacemaker clones
- Maintenance in active Pacemaker clusters
- Managing cron jobs with Pacemaker
- Mandatory and advisory ordering in Pacemaker
- Migrating virtual machines from block-based storage to RADOS/Ceph
- Network connectivity check in Pacemaker
- OCFS2 in Pacemaker (Debian/Ubuntu)
- Solid-state drives and Ceph OSD journals
- Solve a DRBD split-brain in 4 steps
- Testing Pacemaker clusters
- Totem "Retransmit List" in Corosync
- Turning Ceph RBD Images into SAN Storage Devices
- Which OSD stores a specific RADOS object?
- Ceph Tutorial (LCA 2013)
- Ceph: The Storage Stack for OpenStack (OpenStack Israel 2013)
- Die eigene Cloud mit OpenStack Essex (German, LinuxTag 2012)
- Fencing (LCE 2011)
- GlusterFS in HA Clusters (LCEU 2012)
- GlusterFS und Ceph (German, CeBIT 2012)
- Hands-On With Ceph (LCEU 2012)
- High Availability Update (OpenStack Summit Fall 2012)
- High Availability in OpenStack (CloudOpen 2012)
- High Availability in OpenStack (OpenStack Conference Spring 2012)
- Highly Available Cloud: Pacemaker integration with OpenStack (OSCON 2012)
- Mit OpenStack zur eigenen Cloud (German, CLT 2012)
- Mit OpenStack zur eigenen Cloud (German, OSDC 2012)
- More Reliable, More Resilient, More Redundant (OpenStack Summit April 2013)
- MySQL HA Deep Dive (MySQL Conference 2012)
- MySQL High Availability Deep Dive (PLUK 2012)
- MySQL High Availability Sprint (PLUK 2011)
- OpenStack Essex im Praxistest (German, Linuxwochen Wien 2012)
- OpenStack High Availability Update (Grizzly and Havana)
- Roll Your Own Cloud (LCA 2011)
- Storage Replication in HPHA (LCA 2012)
- Zen of Pacemaker (LCA 2012)
- hastexo in 100 Seconds
- Technical documentation
- News releases
- Hints and Kinks
- What we charge
- What others say
DRBD (a registered trademark of LINBIT, who maintain the project) is a solution for redundant data storage within HA setups. It enables you to mirror data from one server over to another, keeping it available even if one of the two servers fails.
We're probably the most experienced DRBD experts you can find. Florian was the original author and maintainer of the DRBD User's Guide, the authoritative reference on DRBD (he has since resigned that role). All of us have deployed DRBD in many different settings and under highly diverse requirements.
What's it good for?
Basically, HA setups are pointless without data redundancy. You must ensure that all your data is just as highly available as your application servers.
There are several approaches to data redundancy. Native SAN replication is usually quite expensive and locks you to a specific vendor. Host-based mirroring with SAN storage often requires redundant fibre links, adding to cost. Application specific replication requires you to learn and deploy multiple distinct (and incompatible) replication facilities in a single stack.
DRBD follows a superior approach: it's a Linux kernel module that enables application-agnostic data replication between two standard, off-the-shelf servers. Think RAID1 device, albeit mirrored between two hosts over a network connection.
HA, DR or both: you decide!
DRBD supports synchronous, semi-synchronous and asynchronous replication. It supports partial, bitmap-based resynchronization and multi-site replication. This makes DRBD extremely useful in high availability, disaster recovery, and combined configurations.
Is it available on my system?
DRBD was integrated into the mainline Linux kernel in February 2009 and comes with almost all modern Linux distributions. Ubuntu and Debian GNU/Linux ship it out of the box, and in SLES, it's part of the High Availability Extension (HAE). On RHEL, it is available as a supported third-party module, and CentOS ships it routinely.
Suffering from strange effects or poor performance while using DRBD? We can help with DRBD consulting services. Straight away. Ask The Expert Now!