A mini-FAQ for JFS
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Last revised December 16, 2002
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Q9. Has JFS been included in the 2.4.x series?

A9. Yes, it was included by Marcelo Tosatti in the 2.4.20 release.
    The 1.1.0 release of JFS is very close to what was released in the 2.4.20 kernel.

Q8. Has JFS been included in the 2.5.x series?

A8. Yes, it was included by Linus in the 2.5.6 release.

Q7. Building the jfsutils package fails with the message uuid.h missing.

A7. Most Linux distros ship this file in e2fsprogs-devel-1.xx.xx.rpm.
    You can also down load it from ext2 utilities web page on sourceforge.
    http://sourceforge.net/project/showfiles.php?group_id=2406

Q6. Does JFS support extended attributes and access control lists?

A6. Yes, there are patches for both of these. The patches start with
    the 1.0.21 release of JFS. You might also need to patch your kernel
    to include the Virtual File System (VFS) layer changes needed to support
    extended attributes and access control lists. The kernel patches for
    the VFS changes are at http://acl.bestbits.at/. The JFS patches for
    extended attributes and access control lists are at 
    http://oss.software.ibm.com/developerworks/patch/?group_id=35

Q5. Can you use the snapshot feature provided by LVM or EVMS on JFS?

A5. Yes, you need release 1.0.22 or above for the file system. The kernel
    must also be built with the VFS locking patch, both LVM and EVMS ship this
    kernel patch.

Q4. Can the log be placed on external device?

A4. Yes, you need release 1.0.18 or above for both the file system and utilities.
	 The -j option is used to create external log
	 example: mkfs.jfs -j /dev/external log /dev/xxxx


Q3. What Linux distributions ship JFS?

A3. The following distributions ship JFS:
	Turbolinux 7.0 Workstation (8/01) was the 1st
	Mandrake 8.1, 8.2, 9.0
	SuSE Linux 7.3, 8.0, 8.1
	United Linux 1.0 (SLES 8.0 x,i,p,z)
	Red Hat 7.3, 8.0 (can't format a JFS partition during install)
	Slackware 8.1
	others ..........

Q2. Can the size of the file system be increased?

A2. Yes, you need release 1.0.21 or above for the file system. The FS must be mounted
     and you need to  use the -o remount option.

	example: mount -o remount,resize /mount point

Q1. What is the history of the source based use for the port of JFS for Linux.

A1. IBM introduced its UNIX file system as the Journaled File System (JFS)
    with the initial release of AIX Version 3.1.  This file system, now
    called JFS1 on AIX, has been the premier file system for AIX over the
    last 10 years and has been installed in millions of customer's AIX
    systems.  In 1995, work began to enhance the file system to be more
    scalable and to support machines that had more than one
    processor. Another goal was to have a more portable file system,
    capable of running on multiple operating systems.
 
    Historically, the JFS1 file system is very closely tied to the memory
    manager of AIX.  This design is typical of a closed-source operating
    system, or a file system supporting only one operating system.
 
    The new Journaled File System, on which the Linux port was based, was
    first shipped in OS/2 Warp Server for eBusiness in April, 1999, after
    several years of designing, coding, and testing.  It also shipped with
    OS/2 Warp Client in October, 2000.  In parallel to this effort, some
    of the JFS development team returned to the AIX Operating System
    Development Group in 1997 and started to move this new JFS source base
    to the AIX operating system.  In May, 2001, a second journaled file
    system, Enhanced Journaled File System (JFS2), was made available for
    AIX 5L.  In December of 1999, a snapshot of the original OS/2 JFS
    source was taken and work was begun to port JFS to Linux.