|

3-way Replication in the Cloud

Posted on November 19, 2008 by Randy Bias

 

It’s been busy here. I’ll announce why soon, but one thing that caught my eye recently that just can’t go by is the imminent open sourcing of DRBD+. DRBD+ is the commercial version of DRBD. This has serious implications for anyone who is serious about building real world cloud applications.

DRBD can be thought of as network-based disk drive mirroring (aka ‘RAID-1′). Essentially, you make sure that all writes to a local disk happen to a remote disk simultaneously or near-simultaneously. Combined with today’s modern journaling filesystems and you have pretty a pretty bullet-proof solution. In the past I’ve used DRBD to build very robust HA clustered appliances and the like. I was also one of the first folks to test it on EC2, although I did not publish results at the time.[1]

DRBD worked extremely well on EC2, but there was always one key drawback: It only mirrors disks between two hosts. Dual redundancy, in this case, isn’t sufficient on EC2. It is quite possible you could lose two hosts; however, the odds of losing three of three are extremely small. That’s where DRBD+ comes in.

One of the most compelling features of DRBD+ is that it allows 3-way or 4-way replication. So, now if you need to build a redundant HA cluster that can not fail on a cloud computing system it’s much much easier than before.

Many kudos to the Linbit team for taking this direction. I think they have opened up an opportunity for cloud solution providers to do some very interesting things.

1. Works great. Very fast replication on EC2 between nodes. Probably even faster on a hardware virtualization platform like GoGrid or FlexiScale.

This entry was posted in Cloud Computing, Technology and tagged . Bookmark the permalink.

|

  • http://yousefourabi.com/blog Yousef Ourabi

    Hey, when you played around with DRBD on EC2 were you using EBS or the standard/ephemeral storage

  • http://neotactics.com randybias

    Yousef, thanks for asking. This was very early last year. January 2007 essentially and I used DRBD with the ephemeral store on a small instance. I recompiled the kernel module, loaded it, and replicated the ephemeral storage (/dev/sdb if I recall correctly). This was a long time before EBS.

Required Reading

Recent Posts

Categories

Discussion


Tags

Administrivia amazon api audits Automation aws cio cloud Cloud Applications cloud futures series cloudscaling commoditization conferences databases decentralization devops EC2 elastic compute cloud enterprise GoGrid hadoop iaas infrastructure Internet Operations Just Plain Cool Lew Tucker Networking open OpenStack paas performance predictions presentations private cloud Rackspace Randy Bias saas scaling Security standards Storage Swift Virtualization vmware web-scale

Cloudscaling Successes

Cloudscaling delivers on open cloud solutions that meet our customers business needs

Open clouds for cloud storage solutions
Open clouds provide cost-competitive public cloud offerings

Cloudscaling Careers

Open clouds are changing the game. You can too, by joining the world's most innovative cloud engineering team. Hack on OpenStack, work with other brilliant minds, and have fun while doing it!
Take a look at our career openings.

May

21

OSBC

OSBC Hyatt Regency San Francisco
San Francisco CA

The 2012 Computerworld Open Source Business Conference will once again present current ideas and implementation case studies bringing open source technologies to broad application. Cloudscaling's Troy Angrignon will present a session on the lessons that market leaders like AWS have to teach, and how those concepts can be applied in open frameworks.

May

22

Open Storage Summit EMEA

Open Storage Summit EMEA Mercure Hotel Amsterdam Aan de Amstel
1096 CJ Amsterdam

This year's Nexenta EMEA gathering will feature in-depth technical tutorials on OpenStorage. Our talk is titled, "Clouds are Complex, But Simplicity Scales." Join us in Amsterdam May 22-24.

© 2012 Cloudscaling   |  
Simplicity scales.