reiserfstune

REISERFSTUNE(8) REISERFSTUNE(8)

NAME
reiserfstune

DESCRIPTION
reiserfstune is used for tuning the ReiserFS journal. It can change two
parameters (journal size and maximum transaction size), and it can move
the journal's location to a new specified block device. (The old Reis-
erFS's journal may be kept unused, or discarded at the user's option.)
Note: At the time of writing this feature was implemented for a special
release of ReiserFS, and was not expected to be put into the mainstream
kernel until approximately Linux 2.5. This means that if you have the
stock kernel you must apply a special patch. Without this patch the
kernel will refuse to mount the newly modified file system. We will
charge $25 to explain this to you if you ask us why it doesn't work.

Perhaps the most interesting application of this code is to put the
journal on a solid state disk.

device is the special file corresponding to the newly specified block
device (e.g /dev/hdXX for IDE disk partition or /dev/sdXX for
the SCSI disk partition).

OPTIONS
-j | --journal-device FILE
FILE is the file name of the block device the file system has
the current journal (the one prior to running reiserfstune) on.
This option is required when the journal is already on a sepa-
rate device from the main data device (although it can be
avoided with --no-journal-available). If you don't specify jour-
nal device by this option, reiserfstune suppose that journal is
on main device.

--no-journal-available
allows reiserfstune to continue when the current journal's block
device is no longer available. This might happen if a disk goes
bad and you remove it (and run fsck).

--journal-new-device FILE
FILE is the file name of the block device which will contain the
new journal for the file system. If you don't specify this,
reiserfstune supposes that journal device remains the
same.

-s | --journal-new-size N
N is the size parameter for the new journal. When journal is to
be on a separate device - its size defaults to number of blocks
that device has. When journal is to be on the same device as the
filesytem - its size defaults to amount of blocks allocated for
journal by mkreiserfs when it created the filesystem. Minimum is
513 for both cases.

-o | --journal-new-offset N
N is an offset in blocks where journal will starts from when
journal is to be on a separate device. Default is 0. Has no
effect when journal is to be on the same device as the filesys-
tem. Most users have no need to use this feature. It can be
used when you want the journals from multiple filesystems to
reside on the same device, and you don't want to or cannot par-
tition that device.

-t | --maximal-transaction-size N
is the maximum transaction size parameter for the new journal.
The default, and max possible, value is 1024 blocks. It should
be less than half the size of the journal. If specifed incor-
rectly, it will be adjusted.

-f | --force
Normally reiserfstune will refuse to change a journal of a file
system that was created before this journal relocation code.
This is because if you change the journal, you cannot go back
(without special option --make-journal-standard) to an old ker-
nel that lacks this feature and be able to use your filesytem.
This option forces it to do that. Specified more than once it
allows to avoid asking for confirmation.

--make-journal-standard
As it was mentioned above, if your file system has non-standard
journal, it can not be mounted on the kernel without journal
relocation code. The thing can be changed, the only condition is
that there is reserved area on main device of the standard jour-
nal size 8193 blocks (it will be so for instance if you convert
standard journal to non-standard). Just specify this option when
you relocate journal back, or without relocation if you already
have it on main device.

-u | --uuid UUID
Set the universally unique identifier ( UUID ) of the
filesystem to UUID (see also uuidgen(8)). The format of the
UUID is a series of hex digits separated by hypthens,
like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".

-l | --label LABEL
Set the volume label of the filesystem. LABEL can be at
most 16 characters long; if it is longer than 16 characters,
reiserfstune will truncate it.

POSSIBLE SCENARIOS OF USING REISERFSTUNE:
1. You have ReiserFS on /dev/hda1, and you wish to have it working with
its journal on the device /dev/journal

boot kernel patched with special "relocatable journal support" patch
reiserfstune /dev/hda1 --journal-new-device /dev/journal -f
mount /dev/hda1 and use.
You would like to change max transaction size to 512 blocks
reiserfstune -t 512 /dev/hda1
You would like to use your file system on another kernel that doesn't
contain relocatable journal support.
umount /dev/hda1
reiserfstune /dev/hda1 -j /dev/journal --journal-new-device /dev/hda1 --make-journal-standard
mount /dev/hda1 and use.

2. You would like to have ReiserFS on /dev/hda1 and to be able to
switch between different journals including journal located on the
device containing the filesystem.

boot kernel patched with special "relocatable journal support" patch
mkreiserfs /dev/hda1
you got solid state disk (perhaps /dev/sda, they typically look like scsi disks)
reiserfstune --journal-new-device /dev/sda1 -f /dev/hda1
Your scsi device dies, it is three in the morning, you have an extra IDE device
lying around
reiserfsck --no-journal-available /dev/hda1
or
reiserfsck --rebuild-tree --no-journal-available /dev/hda1
reiserfstune --no-journal-available --journal-new-device /dev/hda1 /dev/hda1
using /dev/hda1 under patched kernel

AUTHOR
This version of reiserfstune has been written by Vladimir Demidov
<vova@namesys.com> and Edward Shishkin <edward@namesys.com>.

BUGS
Please repoort bugs to the ReiserFS mail list <reiserfs-
list@namesys.com>

SEE ALSO
reiserfsck(8), debugreiserfs(8), mkreiserfs(8)

Reiserfsprogs-3.6.4 January 2002 REISERFSTUNE(8)