XFS supports files and filesystems of 240-1 or 1,099,511,627,775 bytes (one terabyte) on 32-bit systems (IP17, IP20, and IP22). Files up to 263-1 bytes and filesystems of unlimited size are supported on 64-bit systems (IP19, IP21, and IP26). You can use the filesystem interfaces supplied with the IRIS Development Option (IDO) software option to write 32-bit programs that can track 64-bit position and file size. Many programs work without modification because sequential reads succeed even on files larger than 2 GB. NFS allows you to export 64-bit XFS filesystems to other systems.
XFS uses database journaling technology to provide high reliability and rapid recovery. Recovery after a system crash is completed within a few seconds, without the use of a filesystem checker such as the fsck command. Recovery time is independent of filesystem size.
XFS is designed to be a very high performance filesystem. Under certain conditions, throughput exceeds 100 MB per second. Its performance scales to complement the CHALLENGE(TM) MP architecture. While traditional filesystems suffer from reduced performance as they grow in size, with XFS there is no performance penalty.
You can create filesystems with block sizes ranging from 512 bytes to 64 KB. For real-time data, the maximum extent size is 1 GB. Filesystem extents, which provide contiguous data within a file, are configurable at file creation time using the fcntl() system call and are multiples of the filesystem block size. Inodes are created as needed by XFS filesystems. You can specify the size of inodes with the -i option to the filesystem creation command, mkfs. You can also specify the maximum percentage of the space in a filesystem that can be occupied by inodes with the mkfs -i maxpct= option.
Most filesystem commands, such as du, dvhtool, ls, mount, prtvtoc, and umount, work with XFS filesystems as well as EFS filesystems with no user-visible changes. A few commands, such as df, fx, and mkfs have additional features for XFS. The filesystem commands clri, fsck, findblk, and ncheck are not used with XFS filesystems.
For backup and restore, the standard IRIX commands Backup, bru, cpio, Restore, and tar and the optional software product NetWorker® for IRIX can be used for files less than 2 GB in size. To dump XFS filesystems, the new command xfsdump must be used instead of dump. Restoring from these dumps is done using xfsrestore. See Table 3-1 and Table 3-2 in Chapter 3, "Dumping and Restoring XFS Filesystems," for more information about the relationships between xfsdump, xfsrestore, dump, and restore on XFS and EFS filesystems.