HP StorageWorks Clustered File System (software-only) 3.6.1 Windows Storage Server Edition upgrade guide (T4422 - 96001, August 2008)

Chapter 2: Overview 7
Product Changes Affecting the Upgrade
Changes Affecting All Upgrades
PSFS Filesystem Support for Alternate Data Streams
HP Clustered File System 3.6.1 provides filesystem support for Alternate
Data Streams (ADS). This support is enabled by default in PSFS
filesystems created on HP Clustered File System 3.6.1. To use ADS with
an existing PSFS filesystem, you will need to upgrade the filesystem after
the upgrade to 3.6.1 is complete. When ADS support is enabled on a
filesystem, it cannot be later disabled.
The filesystem is upgraded for ADS support with the psfscheck
command, which enables this feature internally in the filesystem.
Consequently, a brief, cluster-wide outage of the filesystem is required
during the upgrade. HP strongly recommends that you enable ADS on all
filesystems.
8.3 Short File Names and Name Tunneling
HP Clustered File System 3.6.1 provides filesystem support for 8.3 Short
File Names (SFN) and name tunneling. This support is disabled by
default. To use these features, you will need to enable them on the
appropriate PSFS filesystems after the upgrade to 3.6.1 is complete.
Filesystems should be upgraded only if you have a specific need for these
features, as the use of 8.3 files causes degradation in filesystem
performance. The degradation is proportional to the number of 8.3 files
created. If 8.3 SFN support is later disabled but 8.3 filenames exist, the
performance degradation will continue. The filesystem is upgraded with
the psfscheck command, which enables this feature internally in the
filesystem. Consequently, a brief, cluster-wide outage of the filesystem is
required during the upgrade.
Changes Affecting Upgrades from 3.4.x
Several product changes in HP Clustered File System affect the upgrade
procedure. Be sure to review the following information before starting
the upgrade.