Jimmy Dean 寫道：
> If for some reason you had WinXP installed on a FAT-32 partition,,
> would it still be able to read any NTFS partitions in the PC?
You should use XFS instead!
>From http://oss.sgi.com/projects/xfs/
Features
The XFS filesystem provides the following major features:
Journaling: Quick Recovery
The XFS journaling technology allows it to restart very quickly after
an unexpected interruption, regardless of the number of files it is
managing. Traditional filesystems must do special filesystem checks
after an interruption, which can take many hours to complete. The XFS
journaling avoids these lengthy filesystem checks.
Fast Transactions
The XFS filesystem provides the advantages of journaling while
minimizing the performance impact of journaling on read and write data
transactions. Its journaling structures and algorithms are tuned to log
the transactions rapidly.
XFS uses efficient tree structures for fast searches and rapid space
allocation. XFS continues to deliver rapid response times, even for
directories with tens of thousands of entries.
High Scalability
XFS is a full 64-bit filesystem, and thus is capable of handling files
as large as a million terabytes.
263 = 9 x 1018 = 9 exabytes
A million terabytes is hundreds of thousands of times larger than most
large filesystems in use today. This may seem to be an extremely large
address space, but it is needed to plan for the exponential
disk-density improvements observed in the disk industry in recent
years. As the disk sizes grow, not only does the address space need to
be sufficiently large, but the structures and algorithms need to scale.
XFS is ready today with the technologies needed for this scalability.
Excellent Bandwidth
XFS as a filesystem is capable of delivering near-raw I/O performance.
XFS has proven scalability on SGI MIPS systems of multiple
gigabytes/sec on multiple terabyte filesystems. As the bandwidth
capabilities of Linux increase, the XFS filesystem is able to utilize
those capabilities.
Technical Specifications
Technology
Journaled 64-bit filesystem with guaranteed filesystem consistency.
Availability
XFS is available for Linux 2.4 and later kernels.
Online Administration
XFS supports filesystem growth for mounted volumes, allows filesystem
"freeze" and "thaw" operations to support volume level snapshots, and
provides an online file defragmentation utility.
Quotas
XFS supports user and group quotas. XFS considers quota information as
filesystem metadata and uses journaling to avoid the need for lengthy
quota consistency checks after a crash.
Extended Attributes
XFS implements fully journaled extended attributes. An extended
attribute is a name/value pair associated with a file. Attributes can
be attached to all types of inodes: regular files, directories,
symbolic links, device nodes, and so forth. Attribute values can
contain up to 64KB of arbitrary binary data. XFS implements three
attribute namespaces: a user namespace available to all users,
protected by the normal file permissions; a system namespace,
accessible only to privileged users; and a security namespace, used by
security modules (SELinux). The system namespace can be used for
protected filesystem meta-data such as access control lists (ACLs) and
hierarchical storage manager (HSM) file migration status.
POSIX Access Control Lists (ACLs)
XFS supports the ACL semantics and interfaces described in the draft
POSIX 1003.1e standard.
Maximum File Size
For Linux 2.4, the maximum accessible file offset is 16TB on 4K page
size and 64TB on 16K page size. For Linux 2.6, when using 64 bit
addressing in the block devices layer (CONFIG_LBD), file size limit
increases to 9 million terabytes (or the device limits).
Maximum Filesystem Size
For Linux 2.4, 2 TB. For Linux 2.6 and beyond, when using 64 bit
addressing in the block devices layer (CONFIG_LBD) and a 64 bit
platform, filesystem size limit increases to 9 million terabytes (or
the device limits). For these later kernels on 32 bit platforms, 16TB
is the current limit even with 64 bit addressing enabled in the block
layer.
Filesystem Block Size
The minimum filesystem block size is 512 bytes. The maximum filesystem
block size is the page size of the kernel, which is 4K on x86
architecture and is set as a kernel compile option on IA-64
architecture.
Filesystem extents (contiguous data) are configurable at file creation
time using fcntl and are multiples of the filesystem block size. Single
extents can be up to 4 GB in size.
Physical Disk Sector Sizes Supported
512 bytes through to 32 kilobytes (in powers of 2), with the caveat
that the sector size must be less than or equal to the filesystem
blocksize.
NFS Compatibility
With NFS version 3, 64-bit filesystems can be exported to other systems
that support the NFS V3 protocol. Systems that use NFS V2 protocol may
access XFS filesystems within the 32-bit limit imposed by the protocol.
Windows Compatibility
SGI uses the Open Source Samba server to export XFS filesystems to
Microsoft Windows systems. Samba speaks the SMB (Server Message Block)
and CIFS (Common Internet File System) protocols.
Backup/Restore
xfsdump and xfsrestore can be used for backup and restore of XFS file
systems to local/remote SCSI tapes or files. It supports dumping of
extended attributes and quota information. As the xfsdump format has
been preserved and is now endian neutral, dumps created on one platform
can be restored onto an XFS filesystem on another (different
architectures, and even different operating systems - IRIX to Linux,
and vice-versa).
Support for Hierarchical Storage
The Data Management API (DMAPI/XDSM) allows implementation of
hierarchical storage management software with no kernel modifications
as well as high-performance dump programs without requiring "raw"
access to the disk and knowledge of filesystem structures.
Optional Realtime Allocator
XFS supports the notion of a "realtime subvolume" - a separate area of
disk space where only file data is stored. Space on this subvolume is
managed using the realtime allocator (as opposed to the default, B+
tree space allocator). The realtime subvolume is designed to provide
very deterministic data rates suitable for media streaming
applications.
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