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System Administration Guide: Basic Administration

What's New in File Systems?

This section describes new file system features in the Solaris 9 release.

Extended File Attributes

The UFS, NFS, and TMPFS file systems have been enhanced to include extended file attributes, which enable application developers to associate specific attributes to a file. For example, a developer of a windowing system file management application might choose to associate a display icon with a file. Extended file attributes are logically represented as files within a hidden directory that is associated with the target file.

You can use the runat command to add attributes and execute shell commands in the extended attribute name space, which is a hidden attribute directory that is associated with the specified file.

To use the runat command to add attributes to a file, you first have to create the attributes file.


$ runat filea cp /tmp/attrdata attr.1

Then, use the runat command to list the attributes of a file.


$ runat filea ls -l

For more information, see the runat(1) man page.

Many Solaris file system commands have been modified to support file system attributes by providing an attribute-aware option that you can use to query, copy, or find file attributes. For more information, see the specific man page for each file system command.

UFS Snapshots

You can use the fssnap command to create a read-only snapshot of a file system. A snapshot is a file system's temporary image that is intended for backup operations.

See Chapter 47, Using UFS Snapshots (Tasks) for more information.

Improved UFS Direct I/O Concurrency

The performance of direct I/O, which is used by database applications to access unbuffered file system data, has been improved by allowing concurrent read and write access to regular UFS files. Previously, an operation that updated file data would lock out all other read or write accesses until the update operation was completed.

Concurrent writes are restricted to the special case of file rewrites. If the file is being extended, writing is single threaded as before. Generally, databases pre-allocate files and seldomly extend them thereafter. Therefore, the effects of this enhancement are evident during normal database operations.

The direct I/O improvements brings I/O bound database performance on a UFS file system to about 90% of raw partition access speeds. If the database is CPU bound or bus bandwidth bound, there might be no improvement.

Consider running your I/O database applications with direct I/O enabled if you are already using UFS to store database tables. Use your database administrative procedures to enable direct I/O, if possible. If there is no way to enable direct I/O through your database product, use the mount -forcedirectio option to enable direct I/O for each file system. Or, use the directio(3C) library call to enable direct I/O.

See mount_ufs(1M) or directio(3C) for more information.

Improved mkfs Performance

The mkfs command now has improve performance when you create file systems. Improved mkfs performance is often 10 times faster than in previous Solaris releases. Performance improvements occur on systems when you create both large and small file systems. However, the biggest performance improvements occur when creating file systems on systems with high-capacity disks or high-speed disks.

New labelit Options for UDF File Systems

The labelit command provides new options for use with Universal Disk Format (UDF) file systems. You can use the new labelit command options to identify the author name, organization, and contact information for a UDF volume.

There was no mechanism to update this information, which is part of general UDF file systems, in previous Solaris releases.

The new UDF specific options for the labelit command, specified with the -o option, are the following:

The maximum length for each option is 35 bytes.

For more information, see labelit_udfs(1M).