CowInstances
- Launchpad Entry: NovaSpec:lvm-instances
- Created: 11/01/10
- Contributors: Vish Ishaya
Summary
Right now, instance disks are stored as files in the system and manually partitioned. This leads to very slow load times and a lot of redundant data. Instances should use Logical Volumes with Copy on Write to conserve space and speed up launch times.
Release Note
Nova now saves instance data using logical volumes. This allows for fast allocation of new images, with no need to manually partition the image. Since disks are no longer manually partitioned, the root drive is available as /dev/vda and local storage for new instances will be available as /dev/vdb. This replaces the older usage of /dev/vda1 and /dev/vda2. To use the older method of allocation, you can turn off lvm support by setting --nouse_lvm in nova-compute.
Placeholder
data below is still being worked on
Rationale
User stories
Assumptions
Design
You can have subsections that better describe specific parts of the issue.
Implementation
This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like:
UI Changes
Should cover changes required to the UI, or specific UI that is required to implement this
Code Changes
Code changes should include an overview of what needs to change, and in some cases even the specific details.
Migration
Include:
- data migration, if any
- redirects from old URLs to new ones, if any
- how users will be pointed to the new way of doing things, if necessary.
Test/Demo Plan
This need not be added or completed until the specification is nearing beta.
Unresolved issues
This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved.
BoF agenda and discussion
Use this section to take notes during the BoF; if you keep it in the approved spec, use it for summarising what was discussed and note any options that were rejected.
