UFS Logging Guidelines

• For logging and master devices - Place logging devices and master device that belong to the same trans metadevice on separate drives and controllers.

• For trans metadevices and shared logging devices - Trans metadevices can share metadevice logging devices. But file systems with the heaviest loads should have separate logs.

• For small file systems - Small file systems with mostly read operations probably do not need to be logged.

• For mirroring logging devices - Mirror all logging devices whenever possible. Losing the data in a log because of device errors can leave a file system in an inconsistent state which fsck(1M) may not be able to repair without user intervention.

• Larger logging devices result in greater concurrency.