64-bit: Support of Multiterabyte UFS File Systems

This Solaris release provides support for multiterabyte UFS file systems on systems that run a 64-bit Solaris kernel.

Previously, UFS file systems were limited to approximately 1 terabyte on both 64-bit and 32-bit systems. All UFS file system commands and utilities have been updated to support multiterabyte UFS file systems.

For example, the ufsdump command has been updated with a larger block size for dumping large UFS file systems:

# ufsdump 0f /dev/md/rdsk/d97 /dev/md/rdsk/d98
    DUMP: Date of this level 0 dump: Fri Oct 10 17:22:13 2008
    DUMP: Date of last level 0 dump: the epoch
    DUMP: Dumping /dev/md/rdsk/d97 to /dev/md/rdsk/d98
    DUMP: Mapping (Pass I) [regular files]
    DUMP: Mapping (Pass II) [directories]
    DUMP: Writing 32 Kilobyte records
    DUMP: Estimated 17439410 blocks (8515.34MB).
    DUMP: Dumping (Pass III) [directories]
    DUMP: Dumping (Pass IV) [regular files]

Administering UFS file systems that are less than 1 terabyte remains the same. No administration differences exist between UFS file systems that are less than one terabyte and file systems that are greater than 1 terabyte.

You can initially create a UFS file system that is less than 1 terabyte and specify that it can eventually be expanded into a multiterabyte file system by using the newfs -T option. This option sets the inode and fragment density to scale appropriately for a multiterabyte file system.

Using the newfs -T option when you create a UFS file system less than 1 terabyte on a system running a 32-bit kernel enables you to eventually expand this file system by using the growfs command when you boot this system under a 64-bit kernel. For more information, see newfs(1M).

You can use the fstyp -v command to identify whether a UFS file system has multiterabyte support by checking the following value in the magic column:

# /usr/sbin/fstyp -v /dev/md/rdsk/d3 | head -5
ufs
magic   decade  format  dynamic time    Thu Jul 17 11:15:36 2008

A UFS file system with no multiterabyte support has the following fstyp output:

# /usr/sbin/fstyp -v /dev/md/rdsk/d0 | head -5
ufs
magic   11954   format  dynamic time    Thu Jul 17 12:43:29 MDT 2008

You can use the growfs command to expand a UFS file system to the size of the slice or the volume without loss of service or data. For more information, see growfs(1M).

Two new related features are multiterabyte volume support with the EFI disk label and multiterabyte volume support with Solaris Volume Manager. For more information, see EFI Disk Label and the Solaris Volume Manager Administration Guide.

Features of Multiterabyte UFS File Systems

Multiterabyte UFS file systems include the following features:

• Provides the ability to create a UFS file system up to 16 terabytes in size.

• Provides the ability to create a file system less than 16 terabytes that can later be increased in size up to 16 terabytes.

• Multiterabyte file systems can be created on physical disks, Solaris Volume Manager's logical volumes, and Veritas' VxVM logical volumes.

• Multiterabyte file systems benefit from the performance improvements of having UFS logging enabled. Multiterabyte file systems also benefit from the availability of logging because the fsck command might not have to be run when logging is enabled.

• When you create a partition for your multiterabyte UFS file system, the disk will be labeled automatically with an EFI disk label. For more information on EFI disk labels, see EFI Disk Label.

• Provides the ability to snapshot a multiterabyte file system by creating multiple backing store files when a file system is over 512 Gbytes.

Limitations of Multiterabyte UFS File Systems

Limitations of multiterabyte UFS file systems are as follows:

• This feature is not supported on 32-bit systems.

• You cannot mount a file system greater than 1 terabyte on a system that is running a 32-bit Solaris kernel.

• You cannot boot from a file system greater than 1 terabyte on a system that is running a 64-bit Solaris kernel. This limitation means that you cannot put a root (/) file system on a multiterabyte file system.

• There is no support for individual files greater than 1 terabyte.

• The maximum number of files is 1 million files per terabyte of a UFS file system. For example, a 4-terabyte file system can contain 4 million files.

  This limit is intended to reduce the time it takes to check the file system with the fsck command.

• The maximum quota that you can set on a multiterabyte UFS file system is 2 terabytes of 1024-byte blocks.

Where to Find Multiterabyte UFS Tasks

Use these references to find step-by-step instructions for working with multiterabyte UFS file systems.