[openstack-dev] Cinder DSL for RAID layouts

Robert Collins robertc at robertcollins.net
Mon Apr 22 04:30:30 UTC 2013

@ the summit John and I talked through the baremetal-cinder stuff in
the hallway track, which can be summarised as two separate features:
 - have a tiny cinder driver that calls the baremetal REST service
 - add a way to describe hardware RAID layouts so that baremetal
volumes can be configured appropriately.

Ideally the RAID layout descriptions can be used for other cinder
drivers that can configure RAID within their storage (whether that is
lvm or 3par or whatever).

So - I'd like us to get some consensus on the layouts that folk need
to describe, and the parameters needed for those layouts.

For bare metal, based on the discussions I've had with folk so far, we
need to be able to force JBOD (disable any RAID controller and let
folk build their own storage redundancy [e.g. if they are running
swift]), or the usual levels - 0/1/6/10. There are two parameters I
care about - number of spindles, total usable storage in the layout.
However, some folk may care about hot spares - I'm not sure if it is a
good idea to model that.

In terms of expressing this, here is a super simple strawman - just
have a three parameters:
level=<'jbod'/'0'/'1'/'6'/'10'>, min_devices=<int>, size_bytes: <int>

so an example request might say level=10, min_devices=8,


Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Cloud Services

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