Upgrading to a New Version of Lustre

Procedures for upgrading your Lustre file system to a new version of Lustre or downgrading to a previously installed version are described below.

Overview
This section provides information about supported upgrades, upgrade paths, and interoperability of nodes with different versions of Lustre installed.

Supported Upgrades
For Lustre 1.8.x, the following upgrades are supported:
 * Lustre 1.6.x to Lustre 1.8.0.
 * One minor version to the next (for example, 1.8.0 > 1.8.x).

Put the rest of this in the downgrade section if included in wiki topic For Lustre 1.8.0, downgrades in the same ranges are supported.
 * If you upgrade from Lustre 1.6.x > 1.8.0, you can downgrade to version 1.6.x.
 * If you upgrade from one minor version to the next (for example Lustre 1.8.0 > 1.8.x), you can downgrade to an earlier minor version (e.g., version 1.8.x).

Caution: A fresh installation of Lustre 1.8.x is not guaranteed to be downgradable to an earlier Lustre version.

Supported Upgrade Paths
These two Lustre upgrade paths are supported. Either can be applied to the entire file system or a combination of the two can be used to upgrade individual servers / clients.


 * Servers can undergo a "rolling upgrade", in which individual servers (or their failover partners) and clients are upgraded one at a time and restarted, so that the file system never goes down. This type of upgrade limits your ability to change certain parameters.
 * The entire file system can be shut down and all servers and clients upgraded at once.

For supported upgrade paths for earlier releases, see Upgrading from 1.4.6 and later to 1.6.

Interoperability between Nodes with different versions of Lustre installed?
This describes the interoperability between clients, OSTs, and MDTs with different versions of Lustre installed??.

Does "old" mean a node with any older version of Lustre installed or just 1.6.x?

Does "new" mean specifically 1.8.x??

Does "mixed" mean a group of servers, some with older versions of Lustre and some with newer versions of Lustre installed?

Clients old MDT).
 * Old live clients can continue to communicate with old/new/mixed servers.
 * Old clients can start up using old/new/mixed servers.
 * New clients can start up using old/new/mixed servers (use old mount format for

OSTs means "after the MDT has been upgraded.")
 * New clients/MDTs can continue to communicate with old OSTs.
 * New OSTs can only be started after the MGS has been started (typically this

MDTs
 * New clients can communicate with old MDTs.
 * New co-located MGS/MDTs can be started at any point.
 * New non-MGS MDTs can be started after the MGS starts.

Note: The limitation with interoperability is that old clients cannot mount a file system which was created by a new MDT.

Keep these
 * Change Log 1.8
 * Upgrading from 1.4.6 and later to 1.6
 * Change Log 1.6

Find a place for this note Note: In Lustre version 1.6 and later, the file system name (--fsname parameter) is limited to 8 characters so that it fits on the disk label.

Prerequisites to Upgrading Lustre
This content was in the OM section "Upgrading from Lustre 1.6.x to Lustre 1.8.0"

What are these procedures? Do they need to be completed before the upgrade is started?

Remember the following points before upgrading Lustre.

The MDT must be upgraded before the OSTs are upgraded.

1. Shut down lconf failover.

2. Install the new modules.

3. Run tunefs.lustre.

4. Mount startup.

A Lustre upgrade can be done across a failover pair.

1. On the backup server, install the new modules.

2. Shut down lconf failover.

3. On the new server, run tunefs.lustre.

4. On the new server, mount startup.

5. On the primary server, install the new modules.

Upgrade procedures
Which topics should be included in the wiki topic and which referred to in the manual (Chapter 13)?

Upgrading from Lustre 1.6.x to Lustre 1.8.0
 * Prerequisites to Upgrading Lustre (see section above)
 * Starting Clients
 * Upgrading a Single File System
 * Upgrading Multiple File Systems with a Shared MGS

Upgrading Lustre 1.8.0 to the Next Minor Version

Downgrading from Lustre 1.8.0 to Lustre 1.6.x
 * Downgrade Requirements
 * Downgrading a File System