1    New and Changed Features

This chapter describes features that are new to the operating system, features that have changed significantly from previous releases, and restrictions to the software and the documentation.

Tru64 UNIX Version 5.1B is a functional release that includes the following enhancements:

1.1    Support for Variable Memory Page Size (Big Pages)

Big pages memory allocation supports mapping a page of virtual memory to 8, 64, or 512 pages of physical memory. Given physical memory's current 8-KB page size, this means that a single page of virtual memory can map to 64, 512, or 4096 KB. Using big pages can minimize the performance penalties that are associated with misses in the translation lookaside buffer. The result can be improved performance for applications that need to map large amounts of data.

Applications can take advantage of increased page size without making changes or rebuilding. Big pages memory allocation has the following characteristics:

By default, the use of variable memory page sizes is disabled. For information about enabling this feature, see sys_attrs_vm(5) and the System Configuration and Tuning guide.

1.2    IPv6 Enhancements

The following enhancements and changes to IPv6 have been incorporated into this release of the operating system:

1.3    Parallel Bus Scan

Parallel scanning is a new feature in Tru64 UNIX Version 5.1B that is designed to shorten the system's boot time. Parallel scanning is disabled in the default system configuration. See the Hardware Management manual for information on using this feature.

When you enable parallel scanning of SCSI and Fibre Channel buses, the system initiates the scan on all buses simultaneously (rather than sequentially). This feature reduces the time required to find devices. On systems with moderate to large numbers of storage devices, the reduction of time required to boot can be significant.

1.4    LSM Fast Plex Attach

For mirrored LSM volumes, you can use the Fast Plex Attach feature to make a temporary copy of the volume data available for backup. You use the temporary volume to perform your backups, leaving the original volume running and available for use. You can use this feature on any mirrored volume on a standalone system or a cluster, including rootvol and cluster_rootvol, except volumes used for swap space. See the Logical Storage Manager manual for more information.

The temporary (secondary) volume is created from one complete plex (mirror) from the original mirrored volume (the primary volume).

Both the primary and secondary volumes use a Fast Plex Attach log, which tracks the regions that change in each volume, similar to a Dirty Region Log. When the plex that created the secondary volume (the migrant plex) is reattached to the original volume, the two FPA logs are merged. Only the regions that changed in the original volume are written to the returning migrant plex, resynchronizing the plex with the original volume in much less time than usually required. The FPA log also ensures that changes to the secondary volume are in effect thrown away, and that the corresponding regions from the primary volume are also written to the returning migrant plex.

1.5    Ensuring Metadata Integrity by Freezing Domains

The freezefs command causes a domain to enter into a metadata-consistent state and guarantees that it stays that way until it is explicitly thawed with the thawfs command, or the freeze time expires. All of the filesets in the domain are frozen. All metadata, which could be spread across multiple volumes or logical units (LUNs), is flushed to disk and does not change for the duration of the freeze.

When you freeze a file system, all in-process file system operations are allowed to complete. Some file system operations that do not require metadata updates (for example, read) work normally even if the file system is frozen.

Once frozen, the file system remains in this metadata-consistent state until it is thawed:

See freezefs(8) and the Cluster Installation manual for more information.

1.6    The vfast Utility

The vfast utility runs at the operating system level with low overhead, continuously defragmenting and balancing files, consolidating free space and distributing the file I/O over the volumes of a domain. It only processes files that are actively being opened and closed. The utility automatically runs during periods of low system demand so that system administrators do not have to take a system off line.

The vfast utility balances the available free space over volumes to maximize file-creation performance. It defragments all active files including the frag file and the root tag file. The system administrator does not need to perform balance and defragment maintenance tasks. The utility also uses file I/O statistics gathered by the AdvFS kernel to distribute files with high I/O to different volumes in the domain.

The vfast utility takes into account reserved file access, but it does not move any of the reserved files.

1.7    LUN/UNIT Expansion

You can increase the amount of storage available in your domain by enlarging the size of an existing volume. For example, LSM and hardware RAID controllers support dynamically increasing the size of a volume.

Because expanding the size of an LSM or hardware RAID volume is done independently of AdvFS, you must notify the domain when the size of a volume changes by using the mount command with the -o extend option.

If the fileset is not already mounted, enter:

mount -o extend domain#fileset /mountpoint

If the fileset is already mounted, enter:

mount -u -o extend domain#fileset /mountpoint

For non-LSM volumes, you must first modify the disk label to include additional storage. See disklabel(8)for more information.

When you use the -o extend option, all additional storage is available to all filesets in the domain.

1.8    Security

The following notes describe changes and enhancements to the security features of the operating system.

1.8.1    Secure Shell

The Secure Shell software is client/server software that provides a suite of network commands to create a secure connection for all data that is exchanged via a Secure Shell command.

You can use the Secure Shell commands in addition to or in place of traditional nonsecure network commands. The following table describes the traditional nonsecure network commands and the equivalent Secure Shell command:

Traditional Commands Equivalent Secure Shell Commands
rsh ssh2
rlogin or telnet ssh2
rcp or ftp scp2 or sftp

1.8.2    Single Sign On Moved to the Operating Ssystem CD-ROM

Single Sign On (SSO) is optional client/server software that uses Kerberos technology to provide secure communication for the ftp, rcp, rlogin, rsh, and telnet network commands and for applications that use Kerberos.

The OSFSSOW2K540 software subset that contains the SSO software has been moved from the Associated Products CD-ROM, Volume 2, to the Tru64 UNIX Operating System CD-ROM. In order to load this subset, you must select it from the list of optional subsets.

1.8.3    Common Data Security Architecture (CDSA)

CDSA shipped as an Advanced Developers Kit with Version 5.1 and Version 5.1A. With this release of the operating system, CDSA is integrated into the base operating system. CDSA provides the following infrastructure for security services:

For more information, see CDSA_intro(3) and the Security Programming manual.

1.8.4    Support for /dev/random

This release of the operating system provides support for /dev/random and /dev/urandom character device special files. These files provide an interface to the kernel random number generator. For more information, see random(4) and get_random_bytes(9r) and the Security Programming manual.

1.9    Netscape 6.2.3 Web Client for Tru64 UNIX

This release of the operating system contains the Netscape 6.2.3 Web Client for Tru64 UNIX as well as Netscape Communicator. The Netscape 6 Web client is the next-generation Web client to the popular Netscape Communicator Web client.

Enter the following command from a terminal window to start the Netscape 6 Web client:

# /usr/bin/X11/netscape6

To set Netscape 6 to be the default Web client for the system, run the following script as a privileged user from a console prompt or a terminal window:

# /usr/opt/netscape6/set_default_client

For additional information about the Netscape 6.2.3 Web client for Tru64 UNIX, refer to the release notes by entering the following URL in a Web browser: file:/usr/doc/netscape6/release_notes.html

1.10    I18N Support

The following new internationalization features have been added in this release of the operating system:

1.11    Additional Changes

The following new features also deserve mention: