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Upgrading to a New Version of Lustre
This section provides information about supported upgrades, upgrade paths, and interoperability of nodes with different versions of Lustre installed. It also describes procedures for upgrading your Lustre file system to a new version of Lustre. For information about available releases, see Lustre Release Information.
Interoperability between Nodes with Different Versions of Lustre Installed
Lustre interoperability enables 1.8.x servers ("new" servers) to work with 1.6.x clients ("old" clients), 1.6.x servers ("old" servers) to work with 1.8.x clients ("new" clients), and "mixed" environments with both 1.6.x and 1.8.x servers. For example, half of each OSS failover pair could be upgraded to enable a quick reversion to 1.6 by powering down the 1.8 servers.
Interoperability between clients, OSTs, and MDTs with different versions of Lustre installed is described in the table below.
| Lustre Component | Interoperability with Other Lustre Components |
|---|---|
| Clients | Old live clients can continue to communicate with old, new, or a mix of servers. |
| Old clients can start up using old, new, or a mix of servers. | |
| New clients can start up using old, new, or a mix of servers (use old mount format for old MDT). | |
| Note: Old clients cannot mount a file system that was created by a new MDT. | |
| OSTs | New clients/MDTs can continue to communicate with old OSTs. |
| New OSTs can only be started after the MGS has been started (typically this
means "after the MDT has been upgraded.") | |
| 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. |
Supported Upgrade Paths
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 and clients.
- Rolling upgrade - 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 the ability to change certain parameters.
- Entire file system upgrade - All servers and clients are shut down and upgraded at the same time.
Upgrade procedures
Performing a Complete File System Upgrade
Performing a Rolling Upgrade
Upgrading Lustre 1.8.x to the Next Minor Version
To upgrade Lustre 1.8.x to the next minor version, for example, Lustre 1.8.0.1 > 1.8.x, follow these procedures:
- To upgrade the complete file system or multiple file system components at the same time, requiring a file system shutdown, see Performing a Complete File System Upgrade
- To upgrade one Lustre component (server or client) at a time, while the file system is running, see Performing a Rolling Upgrade
Downgrading from Lustre 1.8.x
For Lustre 1.8.x, the following downgrades are supported:
- If you upgraded from Lustre 1.6.x > 1.8.x, you can downgrade to version 1.6.x.
- If you upgraded from one minor version to the next (for example, Lustre 1.8.0 > 1.8.x), you can downgrade to the earlier minor version.
Caution: A new installation of Lustre 1.8.x is not guaranteed to be downgradable to an earlier Lustre version.
For a procedure to downgrade from Lustre 1.8.x to Lustre 1.6.x, see Chapter 13 in the Lustre Operations Manual
