[ale] School Project to Create Distributed Filesystem

[Ed Cashin]

On Tue, Feb 24, 2009 at 11:57 AM, Greg Freemyer <greg.freemyer at gmail.com> wrote:
> Just thought of another approach.
>
> Layer one = iSCSI or NBD to export raw block devices out of each server.
>
> Layer two = mdraid to create a fault tolerant block device. ie. use
> Raid 10 or Raid 6 etc. to integrate the raw devices into a whole.
>
> Layer three = LinuxHA to control the whole mess.
>
> Then you just throw in a filesystem and NFS support and you're done.
> LinuxHA already has filesystem and nfs control scripts I think.

There's a HOWTO that might be interesting to folks who are
considering this architecture.  It's directed towards a specific
platform, but it is short and generalizes well, since the platform
is based on debian lenny.

  http://support.coraid.com/support/cln/ft/failover-kit.html

The use of md isn't covered, but it's been tested with the
configuration in the HOWTO and works fine as long as the
admin understands clearly that heartbeat must control md
just like it controls filesystem mounting.  Specifically, the
standby must never have md running with its own independent
ideas about the state of the Software RAID.

-- 
  Ed Cashin <ecashin at noserose.net>