About disk layouts


About disk layouts
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The disk layout is the way file system information is stored on disk. On VxFS, several different disk layout versions were created to take advantage of evolving technological developments.

The disk layout versions used on VxFS are:

Version 1	Version 1 disk layout is the original VxFS disk layout provided with pre-2.0 versions of VxFS.	Not Supported
Version 2	Version 2 disk layout supports features such as filesets, dynamic inode allocation, and enhanced security. The Version 2 layout is available with and without quotas support.	Not Supported
Version 3	Version 3 disk layout encompasses all file system structural information in files, rather than at fixed locations on disk, allowing for greater scalability. Version 3 supports files and file systems up to one terabyte in size.	Not Supported
Version 4	Version 4 disk layout encompasses all file system structural information in files, rather than at fixed locations on disk, allowing for greater scalability. Version 4 supports files and file systems up to two terabytes in size. A disk layout Version 4 file system can still be mounted, but this will be disallowed in future releases. Symantec recommends that you upgrade from Version 4 to the latest default disk layout version. You cannot create new file systems with disk layout Version 4. The only operation that you can perform on a file system with disk layout Version 4 is to upgrade the disk layout to a supported version. If you upgrade a file system from disk layout Version 4 to a later version, once the upgrade operation finishes, you must unmount the file system cleanly, then re-mount the file system.	Deprecated
Version 5	Version 5 enables the creation of file system sizes up to 32 terabytes. File sizes can be a maximum of 4 billion file system blocks. File systems larger than 2 TB must be created on a Veritas Volume Manager volume. Version 5 also enables setting up to 1024 access control list (ACL) entries. A disk layout Version 5 file system can still be mounted, but this will be disallowed in future releases. Symantec recommends that you upgrade from Version 5 to the latest default disk layout version. You cannot create new file systems with disk layout Version 5. The only operation that you can perform on a file system with disk layout Version 5 is to upgrade the disk layout to a supported version. If you upgrade a file system from disk layout Version 5 to a later version, once the upgrade operation finishes, you must unmount the file system cleanly, then re-mount the file system.	Deprecated
Version 6	Version 6 disk layout enables features such as multi-volume support, cross-platform data sharing, named data streams, and File Change Log.	Supported
Version 7	Version 7 disk layout enables support for variable and large size history log records, more than 2048 volumes, large directory hash, and SmartTier.	Supported
Version 8	Version 8 disk layout enables support for file-level snapshots.	Supported

Some of the disk layout versions were not supported on all UNIX operating systems. Currently, the Version 4 and later disk layouts can be created, and the Version 5 and later disk layouts can be mounted. Version 7 is the default disk layout version.

The vxupgrade command is provided to upgrade an existing VxFS file system to the Version 5 and later disk layout while the file system remains online. You must upgrade in steps from older to newer layouts.

See the vxupgrade(1M) manual page.

The vxfsconvert command is provided to upgrade Version 2 and 3 disk layouts to the Version 7 disk layout while the file system is not mounted.

See the vxfsconvert(1M) manual page.