Features/MultipathInstall

= Multipath Installation =

Summary
Anaconda adds the ability to correctly identify and set up multipath devices for use as installation targets.

Owner

 * Name: Peter Jones
 * Email: pjones@redhat.com

Current status

 * Targeted release: Fedora ?
 * Last updated: 9-Feb-2010
 * Percentage of completion: 95%

Detailed Description
This feature adds support for installing to a multipath device and booting from such a device.

Benefit to Fedora
This is a hardware enabling feature. It allows Fedora to be installed on machines which were previously problematic.

Scope
This has repercussions in several packages:
 * Anaconda
 * identification/setup before install
 * configure dracut to build a hostonly initrd
 * grubby/kernel:
 * build initrd at the end of the installation rather than as soon as the kernel is installed
 * dracut
 * assemble mpath devices during boot in order to correctly find the root filesystem

How To Test

 * install to a machine with multipath storage.
 * Ideally, test devices should include active/active and active/passive configurations.
 * see if it boots correctly afterwards
 * boot, and then run "dmsetup ls" and "dmsetup table" as root, making sure that the output indicates that / is indeed using a multipath device.

User Experience
During installation, multipath devices should show up on the "multipath" tab under "Specialized Storage Devices", and the constituent devices should not be present.

Dependencies
This depends on changes to:
 * anaconda (80% done (kickstart support is TODO))
 * dracut (100% done)
 * device-mapper-multipath (100% done)
 * lvm (100% done, I think)
 * kernel (100% done)
 * grubby (100% done)

Contingency Plan

 * None necessary - hardware that doesn't install correctly still won't install correctly.

Documentation

 * No separate docs at this time; we will add some for kickstart support. There's also some documentation of the UI as part of the storage design page.

Release Notes

 * anaconda now supports installation to multipath devices.

Comments and Discussion

 * See Talk:Features/MultipathInstall