What's the minimal stable architecture?

asked 2013-05-21 10:00:05 -0600

anonymous user


updated 2013-06-12 06:18:57 -0600

fifieldt gravatar image


I'm considering building a internal OpenStack platform to support our development teams in the first place and in the future maybe to host some of our production servers.

I read through the documentation like four times and already made some decisions:

  • We want our architecture to be reasonable stable. Since the budget will be limited I can imagine that making the whole architecture foolproof is not gonna happen.
  • The setup should support 50 virtual instances with 4GBs of RAM and 100GBs of diskspace.
  • We want to use Xen or XCP.

I considered the following architecture:

  • 4 servers with 96GBs of RAM and 2 TBs of RAID6 storage running XCP and nova-compute.
  • 1 Server with 8GBs of RAM and 600GBs of RAID1 storage running all the other roles.

The Xen Live Migration allows us to put an server in maintenance mode and distribute all instances over the other servers. The only question is what happens if a server crashes before migration can happen? Will the instances survive? As I understand it correctly normally when an instance is stopped its on-server non-shared disks are deleted. I'm okay with instances going down if a server crashes as long as they boot up again after restoring the server. Is this achievable?

Is this architecture workable or would you recommend something else?

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answered 2013-07-16 11:24:33 -0600

armando-migliaccio gravatar image

If the crash is not catastrophic, VM's can boot up after the server has been recovered. They can even boot up automatically. With XCP you can rely on both live and block storage migration. The former requires shared storage, the latter does not (only from XCP 1.6 and OpenStack Folsom).

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Asked: 2013-05-21 10:00:05 -0600

Seen: 373 times

Last updated: Jul 16 '13