Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

These days clustering is becoming synonymous to high availability. As an enterprise architect I have to shake my head in disbelief. IMHO, clustering can be a component of HA but is far from being HA in itself. I'm always used to approaching HA as a solution involving multiple components from replication to mirroring to DR.

Does anyone else feel the same on this topic? Or am i just an grumpy old architect!

share|improve this question
add comment

3 Answers

No, you are obviously right. HA is a goal, and clustering is one technology that helps you reach it.

Clustering will not get you HA if for example everything goes via a single switch...

share|improve this answer
add comment

Depends on your definitions I've always felt - I've always thought integrity of data is key component of HA and clustering doesn't give you this given the shared storage it employs. Any cluster needs to be backed up by a robust backup strategy that would include a blend of mirrors, replication and off-line backups as appropriate to the requirements of the system you're protecting. I've seen first hand examples of a cluster breaking down and there being no other plans in place.

share|improve this answer
add comment

Clustering IMO is just like you thought, just a part of HA. It adds redundancy to prevent single system failure. However, just like any good HA environment, you should remove any single point of failure. Just because the servers are clustered, that doesn't assume multi-pathing to your storage, redundant switches in your network, or even redundant power circuits and PDUs in your rack. Replication is huge too, site failure can kill even the best HA solution unless data goes offsite (tape or otherwise).

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.