.\"
.\" $DragonFly: src/sbin/hammer/hammer.8,v 1.58 2008/11/13 02:04:27 dillon Exp $
.\"
-.Dd September 20, 2009
+.Dd September 28, 2009
.Dt HAMMER 8
.Os
.Sh NAME
.Nd HAMMER file system utility
.Sh SYNOPSIS
.Nm
-.Op Fl h2qrvB
+.Fl h
+.Nm
+.Op Fl 2Bqrvy
.Op Fl b Ar bandwidth
+.Op Fl C Ar cachesize Ns Op Ns Cm \&: Ns Ar readahead
.Op Fl c Ar cyclefile
-.Op Fl f Ar blkdev[:blkdev]*
+.Op Fl f Ar blkdev Ns Oo Ns Cm \&: Ns Ar blkdev Oc Ns *
.\" .Op Fl s Ar linkpath
.Op Fl i Ar delay
.Op Fl t Ar seconds
-.Op Fl C Ar cachesize[:readahead]
.Ar command
.Op Ar argument ...
.Sh DESCRIPTION
Tell the mirror commands to use a 2-way protocol, which allows
automatic negotiation of transaction id ranges.
This option is automatically enabled by the
-.Ar mirror-copy
+.Cm mirror-copy
command.
+.It Fl B
+Bulk Transfer.
+.Cm Mirror-stream
+will not attempt to break-up large initial bulk transfers into smaller pieces.
+This can save time but if the link is lost in the middle of the
+initial bulk transfer you will have to start over from scratch.
.It Fl b Ar bandwidth
Specify a bandwidth limit in bytes per second for mirroring streams.
This option is typically used to prevent batch mirroring operations from
loading down the machine.
The bandwidth may be suffixed with
-.Sq k ,
-.Sq m ,
+.Cm k , m ,
or
-.Sq g
+.Cm g
to specify values in kilobytes, megabytes, and gigabytes per second.
If no suffix is specified, bytes per second is assumed.
+.It Fl C Ar cachesize Ns Op Ns Cm \&: Ns Ar readahead
+Set the memory cache size for any raw
+.Tn I/O .
+The default is 16m.
+A suffix of
+.Cm k
+for kilobytes and
+.Cm m
+for megabytes is allowed,
+else the cache size is specified in bytes.
+.Pp
+The read-behind/read-ahead defaults to 4 hammer blocks.
+.Pp
+This option is typically only used with diagnostic commands
+as kernel-supported commands will use the kernel's buffer cache.
.It Fl c Ar cyclefile
When pruning and reblocking you can instruction
.Nm
.Nm
runs to completion it will delete
.Ar cyclefile .
-.It Fl f Ar blkdev[:blkdev]*
+.It Fl f Ar blkdev Ns Oo Ns Cm \&: Ns Ar blkdev Oc Ns *
Specify the volumes making up a
.Nm HAMMER
file system.
May be specified multiple times.
.It Fl y
Force "yes" for any interactive question.
-.It Fl B
-Bulk Transfer.
-.Ar Mirror-stream
-will not attempt to break-up large initial bulk transfers into smaller
-pieces. This can save time but if the link is lost in the middle of the
-initial bulk transfer you will have to start over from scratch.
-.It Fl C Ar cachesize[:readahead]
-Set the memory cache size for any raw I/O. The default is 16m.
-A suffix of 'k' for kilobytes and 'm' for megabytes is allowed,
-else the cache size is specified in bytes.
-.Pp
-The read-behind/read-ahead defaults to 4 hammer blocks.
-.Pp
-This option is typically only used with diagnostic commands
-as kernel-supported commands will use the kernel's buffer cache.
.El
.Pp
The commands are as follows:
.Bl -tag -width indent
.\" ==== synctid ====
-.It Ar synctid Ar filesystem Op quick
+.It Cm synctid Ar filesystem Op Cm quick
Generates a guaranteed, formal 64 bit transaction id representing the
current state of the specified
.Nm HAMMER
The file system will be synced to the media.
.Pp
If the
-.Ar quick
+.Cm quick
keyword is specified the file system will be soft-synced, meaning that a
crash might still undo the state of the file system as of the transaction
id returned but any new modifications will occur after the returned
transaction id as expected.
.\" ==== bstats ====
-.It Ar bstats Op interval
+.It Cm bstats Op Ar interval
Output
.Nm HAMMER
B-tree statistics until interrupted.
seconds between each display.
The default interval is one second.
.\" ==== iostats ====
-.It Ar iostats Op interval
+.It Cm iostats Op Ar interval
Output
.Nm HAMMER
-I/O statistics until interrupted.
+.Tn I/O
+statistics until interrupted.
Pause
.Ar interval
seconds between each display.
The default interval is one second.
.\" ==== history ====
-.It Ar history Ar path ...
+.It Cm history Ar path ...
Show the modification history for
.Nm HAMMER
file's inode and data.
.\" ==== blockmap ====
-.It Ar blockmap
-Dump the blockmap for the filesystem. The HAMMER blockmap is two-layer
-blockmap representing the maximum possible filesystem size of 1 Exabyte.
+.It Cm blockmap
+Dump the blockmap for the file system.
+The
+.Nm HAMMER
+blockmap is two-layer
+blockmap representing the maximum possible file system size of 1 Exabyte.
Needless to say the second layer is only present for blocks which exist.
-HAMMER's blockmap represents 8-Megabyte blocks. Each block has an append
+.Nm HAMMER Ns 's
+blockmap represents 8-Megabyte blocks, called big-blocks.
+Each big-block has an append
point, a free byte count, and a typed zone id which allows content to be
reverse engineered to some degree.
.Pp
-In HAMMER allocations essentially appended to a selected big-block using
-the append offset and deducted from the free byte count. When space is
-freed the free byte count is adjusted but HAMMER does not track holes in
-big-blocks for reallocation. A big-block must be completely freed, either
-through normal filesystem operations or through reblocking, before
+In
+.Nm HAMMER
+allocations essentially appended to a selected big-block using
+the append offset and deducted from the free byte count.
+When space is freed the free byte count is adjusted but
+.Nm HAMMER
+does not track holes in big-blocks for reallocation.
+A big-block must be completely freed, either
+through normal file system operations or through reblocking, before
it can be reused.
.Pp
Data blocks can be shared by deducting the space used from the free byte
-count for each shared references, though HAMMER does not yet make use of
-this feature. This means the free byte count can legally go negative.
+count for each shared references, though
+.Nm HAMMER
+does not yet make use of this feature.
+This means the free byte count can legally go negative.
.Pp
This command needs the
.Fl f
flag.
.\" ==== show ====
-.It Ar show Op Ar lo:objid
-Dump the B-tree. By default this command will validate all B-Tree
+.It Cm show Op Ar lo Ns Cm \&: Ns Ar objid
+Dump the B-tree.
+By default this command will validate all B-Tree
linkages and CRCs, including data CRCs, and will report the most verbose
information it can dig up.
Any errors will show up with a 'B' in column 1 along with various
If you use
.Fl qqq
the command will not report volume header information, big-block fill
-ratios, mirror TIDs, or report or check data CRCs. B-Tree CRCs and
-linkages are still checked.
+ratios, mirror transaction ids, or report or check data CRCs.
+B-tree CRCs and linkages are still checked.
.Pp
This command needs the
.Fl f
.\" Dump the B-tree, record, large-data, and small-data blockmaps, showing
.\" physical block assignments and free space percentages.
.\" ==== namekey1 ====
-.It Ar namekey1 Ar filename
+.It Cm namekey1 Ar filename
Generate a
.Nm HAMMER
64 bit directory hash for the specified file name, using
-the original directory hash algorithm in version 1 of the filesystem.
+the original directory hash algorithm in version 1 of the file system.
The low 32 bits are used as an iterator for hash collisions and will be
output as 0.
.\" ==== namekey2 ====
-.It Ar namekey2 Ar filename
+.It Cm namekey2 Ar filename
Generate a
.Nm HAMMER
64 bit directory hash for the specified file name, using
-the new directory hash algorithm in version 2 of the filesystem.
+the new directory hash algorithm in version 2 of the file system.
The low 32 bits are still used as an iterator but will start out containing
part of the hash key.
.\" ==== namekey32 ====
-.It Ar namekey32 Ar filename
+.It Cm namekey32 Ar filename
Generate the top 32 bits of a
.Nm HAMMER
64 bit directory hash for the specified file name.
.\" ==== info ====
-.It Ar info
-Shows extended information about all the mounted HAMMER filesystems.
-At the moment volume identification, big blocks information and space details are shown.
+.It Cm info
+Shows extended information about all the mounted
+.Nm HAMMER
+file systems.
+At the moment volume identification, big-blocks information and space details
+are shown.
.\" ==== cleanup ====
-.It Ar cleanup Op Ar filesystem ...
-This is a meta-command which executes snapshot, pruning, and reblocking
+.It Cm cleanup Op Ar filesystem ...
+This is a meta-command which executes snapshot, prune, rebalance and reblock
commands on the specified
.Nm HAMMER
-file system.
+file system(s).
If no
.Ar filesystem
is specified this command will clean-up all
snapshots <period> <retention-time> [any]
prune <period> <max-runtime>
rebalance <period> <max-runtime>
-reblock <period> <1/3 max-runtime>
-recopy <period> <1/3 max-runtime>
-
+reblock <period> <max-runtime>
+recopy <period> <max-runtime>
+.Ed
+.Pp
Defaults are:
-snapshots 1d 60d # 0d 60d for PFS /tmp, /var/tmp, /usr/obj
+.Bd -literal -offset indent
+snapshots 1d 60d # 0d 0d for PFS /tmp, /var/tmp, /usr/obj
prune 1d 5m
rebalance 1d 5m
reblock 1d 5m
.Cm s
meaning day, hour, minute and second.
.Pp
-If the snapshots directive has a period of 0 and a retention time of 0
+If the
+.Cm snapshots
+directive has a period of 0 and a retention time of 0
then snapshot generation is disabled, removal of old snapshots are
disabled, and prunes will use
-.Ar prune-everything .
-If the snapshots directive has a period of 0 but a non-zero retention time
+.Cm prune-everything .
+If the
+.Cm snapshots
+directive has a period of 0 but a non-zero retention time
then this command will not create any new snapshots but will remove old
snapshots it finds based on the retention time.
.Pp
-By default only snapshots in the form: snap-yyyymmdd[-hhmm] are processed.
+By default only snapshots in the form
+.Ql snap- Ns Ar yyyymmdd Ns Op - Ns Ar HHMM
+are processed.
If the
-.Ar any
-directive is specified as a third argument on the snapshots config line
-then any softlink of the form *[- or .]yyyymmdd[-hhmm] will be processed.
+.Cm any
+directive is specified as a third argument on the
+.Cm snapshots
+config line then any softlink of the form
+.Ql *- Ns Ar yyyymmdd Ns Op - Ns Ar HHMM
+or
+.Ql *. Ns Ar yyyymmdd Ns Op - Ns Ar HHMM
+will be processed.
.Pp
A prune max-runtime of 0 means unlimited.
.Pp
If period hasn't passed since the previous
-.Ar cleanup
+.Cm cleanup
run nothing is done.
For example a day has passed when midnight is passed (localtime).
By default,
Reblocking is defragmentation with a level of 95%,
and recopy is full defragmentation.
.Pp
-By default prune, rebalance and reblock operations are limited to 5 minutes per
-function, and recopy operations are limited to 10 minutes per function.
-Reblocking and recopy runs are each broken down into three separate functions
-(btree, inodes and data)
-and are thus by default limited to 15 and 30 minutes respectively.
+By default prune and rebalance operations are time limited to 5 minutes,
+reblock operations to a bit over 5 minutes,
+and recopy operations to a bit over 10 minutes.
+Reblocking and recopy runs are each broken down into four separate functions:
+btree, inodes, dirs and data.
+Each function is time limited to the time given in the configuration file,
+but the btree, inodes and dirs functions usually does not take very long time,
+full defragmentation is always used for these three functions.
Also note that this directive will by default disable snapshots on
the following PFS's:
.Pa /tmp ,
file.
The pruning and reblocking commands automatically maintain a cyclefile
for incremental operation.
-If you interrupt (^C) the program the cyclefile will be updated, but a sub-command
+If you interrupt (^C) the program the cyclefile will be updated,
+but a sub-command
may continue to run in the background for a few seconds until the
.Nm HAMMER
ioctl detects the interrupt.
The
-.Ar snapshots
+.Cm snapshots
PFS option can be set to use another location for the snapshots directory.
.Pp
Work on this command is still in progress.
-Expected additions: An ability to remove snapshots dynamically as the
+Expected additions:
+An ability to remove snapshots dynamically as the
file system becomes full.
.\" ==== expand ====
-.It Ar expand Ar filesystem Ar device
+.It Cm expand Ar filesystem Ar device
This command will format
.Ar device
and add all of its space to
.Ar filesystem .
.Pp
-NOTE! All existing data contained on
+.Em NOTE!
+All existing data contained on
.Ar device
-will be destroyed by this operation! If
+will be destroyed by this operation!
+If
.Ar device
contains a valid
.Nm HAMMER
together with any other device that make the filesystem, colon-separated to
.Xr mount_hammer 8 .
.\" ==== snapshot ====
-.It Ar snapshot Oo Ar filesystem Oc Ar snapshot-dir
+.It Cm snapshot Oo Ar filesystem Oc Ar snapshot-dir
Takes a snapshot of the file system either explicitly given by
.Ar filesystem
or implicitly derived from the
with the current time as parameter.
If
.Ar snapshot-dir
-refers to an existing directory, a default format string of "snap-%Y%d%m-%H%M"
+refers to an existing directory, a default format string of
+.Ql snap-%Y%d%m-%H%M
is assumed and used as name for the newly created symlink.
.Pp
Snapshot is a per PFS operation, so a
/mysnapshots/obj-2008-06-27 -> /obj@@0x10d2cd05b7270d16
.Ed
.\" ==== prune ====
-.It Ar prune Ar softlink-dir
+.It Cm prune Ar softlink-dir
Prune the file system based on previously created snapshot softlinks.
Pruning is the act of deleting file system history.
The
-.Ar prune
-command
-will delete file system history such that
+.Cm prune
+command will delete file system history such that
the file system state is retained for the given snapshots,
-and all history after the latest snapshot,
-but all other history is deleted.
+and all history after the latest snapshot.
+By setting the per PFS parameter
+.Cm prune-min ,
+history is guaranteed to be saved at least this time interval.
+All other history is deleted.
.Pp
The target directory is expected to contain softlinks pointing to
snapshots of the file systems you wish to retain.
The directory is scanned non-recursively and the mount points and
transaction ids stored in the softlinks are extracted and sorted.
The file system is then explicitly pruned according to what is found.
-Cleaning out portions of the file system is as simple as removing a softlink
-and then running the
-.Ar prune
+Cleaning out portions of the file system is as simple as removing a
+snapshot softlink and then running the
+.Cm prune
command.
.Pp
As a safety measure pruning only occurs if one or more softlinks are found
-containing the @@ snapshot id extension.
+containing the
+.Ql @@
+snapshot id extension.
Currently the scanned softlink directory must contain softlinks pointing
to a single
.Nm HAMMER
mount.
The softlinks may specify absolute or relative paths.
-Softlinks must use 20-character (@@0x%016llx) transaction ids,
-as might be returned from
-.Dq Nm Ar synctid filesystem .
+Softlinks must use 20-character
+.Ql @@0x%016llx
+transaction ids, as might be returned from
+.Nm Cm synctid Ar filesystem .
.Pp
Pruning is a per PFS operation, so a
.Nm HAMMER
pruned out.
The file system must be reblocked to completely recover all available space.
.Pp
-Example, lets say your snapshot directory contains the following links:
+Example, lets say your that you didn't set
+.Cm prune-min ,
+and snapshot directory contains the following links:
.Bd -literal -offset indent
lrwxr-xr-x 1 root wheel 29 May 31 17:57 snap1 ->
/usr/obj/@@0x10d2cd05b7270d16
.Ed
.Pp
If you were to run the
-.Ar prune
+.Cm prune
command on this directory, then the
.Nm HAMMER
.Pa /usr/obj
If you then delete the
.Pa snap2
softlink and rerun the
-.Ar prune
+.Cm prune
command,
history for modifications pertaining to that snapshot would be destroyed.
.\" ==== prune-everything ====
-.It Ar prune-everything Ar filesystem
+.It Cm prune-everything Ar filesystem
This command will remove all historical records from the file system.
This directive is not normally used on a production system.
.\" ==== rebalance ====
-.It Ar rebalance Ar filesystem Op Ar saturation_level
-This command will rebalance the B-Tree, nodes with small numbers of
+.It Cm rebalance Ar filesystem Op Ar saturation_level
+This command will rebalance the B-tree, nodes with small number of
elements will be combined and element counts will be smoothed out
between nodes.
.Pp
-The saturation level is a percentage between 50 and 100. The default
-is 75 percent.
+The saturation level is a percentage between 50 and 100.
+The default is 75 percent.
.\" ==== reblock ====
-.It Ar reblock Ar filesystem Op Ar fill_percentage
-.It Ar reblock-btree Ar filesystem Op Ar fill_percentage
-.It Ar reblock-inodes Ar filesystem Op Ar fill_percentage
-.It Ar reblock-dirs Ar filesystem Op Ar fill_percentage
-.It Ar reblock-data Ar filesystem Op Ar fill_percentage
+.It Cm reblock Ar filesystem Op Ar fill_percentage
+.It Cm reblock-btree Ar filesystem Op Ar fill_percentage
+.It Cm reblock-inodes Ar filesystem Op Ar fill_percentage
+.It Cm reblock-dirs Ar filesystem Op Ar fill_percentage
+.It Cm reblock-data Ar filesystem Op Ar fill_percentage
Attempt to defragment and free space for reuse by reblocking a live
.Nm HAMMER
file system.
-Big blocks cannot be reused by
+Big-blocks cannot be reused by
.Nm HAMMER
until they are completely free.
This command also has the effect of reordering all elements, effectively
.Nm HAMMER
file system and each PFS in it have to be reblocked separately.
.\" ==== pfs-status ====
-.It Ar pfs-status Ar dirpath ...
+.It Cm pfs-status Ar dirpath ...
Retrieve the mirroring configuration parameters for the specified
.Nm HAMMER
file systems or pseudo-filesystems (PFS's).
.\" ==== pfs-master ====
-.It Ar pfs-master Ar dirpath Op options
+.It Cm pfs-master Ar dirpath Op Ar options
Create a pseudo-filesystem (PFS) inside a
.Nm HAMMER
file system.
for use as a replication source or target.
.Pp
The
-.Ar pfs-master
+.Cm pfs-master
directive creates a PFS that you can read, write, and use as a mirroring
source.
.Pp
mount to access a PFS, for more information see
.Xr HAMMER 5 .
.\" ==== pfs-slave ====
-.It Ar pfs-slave Ar dirpath Op options
+.It Cm pfs-slave Ar dirpath Op Ar options
Create a pseudo-filesystem (PFS) inside a
.Nm HAMMER
file system.
for use as a replication source or target.
.Pp
The
-.Ar pfs-slave
+.Cm pfs-slave
directive creates a PFS that you can use as a mirroring target.
You will not be able to access a slave PFS until you have completed the
first mirroring operation with it as the target (its root directory will
not exist until then).
.Pp
-Access to the pfs-slave via the special softlink,
-as described in the
+Access to the pfs-slave via the special softlink, as described in the
.Sx PFS NOTES
below, allows
.Nm HAMMER
calls.
.Pp
A PFS can only be truly destroyed with the
-.Ar pfs-destroy
+.Cm pfs-destroy
directive.
Removing the softlink will not destroy the underlying PFS.
.Pp
mount to access a PFS, for more information see
.Xr HAMMER 5 .
.\" ==== pfs-update ====
-.It Ar pfs-update Ar dirpath Op options
+.It Cm pfs-update Ar dirpath Op Ar options
Update the configuration parameters for an existing
.Nm HAMMER
-file system
-or pseudo-filesystem.
+file system or pseudo-filesystem.
Options that may be specified:
.Bl -tag -width indent
-.It sync-beg-tid=0x16llx
+.It Cm sync-beg-tid= Ns Ar 0x16llx
This is the automatic snapshot access starting transaction id for
mirroring slaves.
This parameter is normally updated automatically by the
-.Ar mirror-write
+.Cm mirror-write
directive.
.Pp
It is important to note that accessing a mirroring slave
id can result in an unreliable snapshot since you will be accessing
data that is still undergoing synchronization.
.Pp
-Manually modifying this field is dangerous and can result in a broken
-mirror.
-.It sync-end-tid=0x16llx
+Manually modifying this field is dangerous and can result in a broken mirror.
+.It Cm sync-end-tid= Ns Ar 0x16llx
This is the current synchronization point for mirroring slaves.
This parameter is normally updated automatically by the
-.Ar mirror-write
+.Cm mirror-write
directive.
.Pp
Manually modifying this field is dangerous and can result in a broken mirror.
-.It shared-uuid=<uuid>
+.It Cm shared-uuid= Ns Ar uuid
Set the shared UUID for this file system.
All mirrors must have the same shared UUID.
For safety purposes the
-.Ar mirror-write
+.Cm mirror-write
directives will refuse to operate on a target with a different shared UUID.
.Pp
Changing the shared UUID on an existing, non-empty mirroring target,
including an empty but not completely pruned target,
can lead to corruption of the mirroring target.
-.It unique-uuid=<uuid>
+.It Cm unique-uuid= Ns Ar uuid
Set the unique UUID for this file system.
This UUID should not be used anywhere else,
even on exact copies of the file system.
-.It label=<string>
+.It Cm label= Ns Ar string
Set a descriptive label for this file system.
-.It snapshots=<string>
+.It Cm snapshots= Ns Ar string
Specify the snapshots directory which
.Nm
-.Ar cleanup
+.Cm cleanup
will use to manage this PFS.
The snapshots directory does not need to be configured for
PFS masters and will default to
.Pa <name>
is an appropriate label.
You can control snapshot retention on your slave independent of the master.
-.It snapshots-clear
-Zero out the snapshots directory path for this PFS.
-.It prune-min=Nd
-.It prune-min=Nd/hh[:mm[:ss]]
-.It prune-min=hh[:mm[:ss]]
+.It Cm snapshots-clear
+Zero out the
+.Cm snapshots
+directory path for this PFS.
+.It Cm prune-min= Ns Ar N Ns Cm d
+.It Cm prune-min= Ns Xo
+.Op Ar N Ns Cm d/ Ns
+.Ar hh Ns Op Cm \&: Ns Ar mm Ns Op Cm \&: Ns Ar ss
+.Xc
Set the minimum fine-grained data retention period.
.Nm HAMMER
always retains fine-grained history up to the most recent snapshot.
You can extend the retention period further by specifying a non-zero
-pruning minimum. Any snapshot softlinks within the retention period
-are ignored for the purposes of pruning (the fine grained history
-is retained).
+pruning minimum.
+Any snapshot softlinks within the retention period are ignored
+for the purposes of pruning (the fine grained history is retained).
+Number of days, hours, minutes and seconds are given as
+.Ar N , hh , mm
+and
+.Ar ss .
.Pp
Because the transaction id in the snapshot softlink cannot be used
to calculate a timestamp,
.Nm HAMMER
-uses the earlier of the st_ctime or st_mtime field of the softlink to
+uses the earlier of the
+.Fa st_ctime
+or
+.Fa st_mtime
+field of the softlink to
determine which snapshots fall within the retention period.
Users must be sure to retain one of these two fields when manipulating
the softlink.
.El
.\" ==== pfs-upgrade ====
-.It Ar pfs-upgrade Ar dirpath
+.It Cm pfs-upgrade Ar dirpath
Upgrade a PFS from slave to master operation.
-The PFS will be rolled back to the current end synchronization tid
+The PFS will be rolled back to the current end synchronization transaction id
(removing any partial synchronizations), and will then become writable.
.Pp
.Em WARNING!
This directive will refuse to run if any programs have open descriptors
in the PFS, including programs chdir'd into the PFS.
.\" ==== pfs-downgrade ====
-.It Ar pfs-downgrade Ar dirpath
+.It Cm pfs-downgrade Ar dirpath
Downgrade a master PFS from master to slave operation
The PFS becomes read-only and access will be locked to its
-.Ar sync-end-tid .
+.Cm sync-end-tid .
.Pp
This directive will refuse to run if any programs have open descriptors
in the PFS, including programs chdir'd into the PFS.
.\" ==== pfs-destroy ====
-.It Ar pfs-destroy Ar dirpath
+.It Cm pfs-destroy Ar dirpath
This permanently destroys a PFS.
.Pp
This directive will refuse to run if any programs have open descriptors
in the PFS, including programs chdir'd into the PFS.
.\" ==== mirror-read ====
-.It Ar mirror-read Ar filesystem Op Ar <begin-tid>
+.It Cm mirror-read Ar filesystem Op Ar begin-tid
Generate a mirroring stream to stdout.
The stream ends when the transaction id space has been exhausted.
.\" ==== mirror-read-stream ====
-.It Ar mirror-read-stream Ar filesystem Op Ar <begin-tid>
+.It Cm mirror-read-stream Ar filesystem Op Ar begin-tid
Generate a mirroring stream to stdout.
Upon completion the stream is paused until new data is synced to the
master, then resumed.
Operation continues until the pipe is broken.
.\" ==== mirror-write ====
-.It Ar mirror-write Ar filesystem
+.It Cm mirror-write Ar filesystem
Take a mirroring stream on stdin.
.Pp
This command will fail if the
-.Ar shared-uuid
+.Cm shared-uuid
configuration field for the two file systems do not match.
.Pp
If the target PFS does not exist this command will ask you whether
you want to create a compatible PFS slave for the target or not.
.\" ==== mirror-dump ====
-.It Ar mirror-dump
+.It Cm mirror-dump
A
-.Ar mirror-read
+.Cm mirror-read
can be piped into a
-.Ar mirror-dump
+.Cm mirror-dump
to dump an ASCII representation of the mirroring stream.
.\" ==== mirror-copy ====
-.It Ar mirror-copy Ar [[user@]host:]filesystem Ar [[user@]host:]filesystem
+.\".It Cm mirror-copy Ar [[user@]host:]filesystem [[user@]host:]filesystem
+.It Cm mirror-copy Xo
+.Oo Oo Ar user Oc Ns Cm @ Ns Ar host Ns Cm \&: Oc Ns Ar filesystem
+.Oo Oo Ar user Oc Ns Cm @ Ns Ar host Ns Cm \&: Oc Ns Ar filesystem
+.Xc
This is a shortcut which pipes a
-.Ar mirror-read
+.Cm mirror-read
command to a
-.Ar mirror-write
+.Cm mirror-write
command.
If a remote host specification is made the program forks a
.Xr ssh 1
and execs the
-.Ar mirror-read
+.Cm mirror-read
and/or
-.Ar mirror-write
+.Cm mirror-write
on the appropriate host.
The source may be a master or slave PFS, and the target must be a slave PFS.
.Pp
the two-way protocol feature which automatically negotiates transaction id
ranges without having to use a cyclefile.
If the operation completes successfully the target PFS's
-.Ar sync-end-tid
+.Cm sync-end-tid
will be updated.
Note that you must re-chdir into the target PFS to see the updated information.
If you do not you will still be in the previous snapshot.
If the target PFS does not exist this command will ask you whether
you want to create a compatible PFS slave for the target or not.
.\" ==== mirror-stream ====
-.It Ar mirror-stream Ar [[user@]host:]filesystem Ar [[user@]host:]filesystem
+.\".It Cm mirror-stream Ar [[user@]host:]filesystem [[user@]host:]filesystem
+.It Cm mirror-stream Xo
+.Oo Oo Ar user Oc Ns Cm @ Ns Ar host Ns Cm \&: Oc Ns Ar filesystem
+.Oo Oo Ar user Oc Ns Cm @ Ns Ar host Ns Cm \&: Oc Ns Ar filesystem
+.Xc
This command works similarly to
-.Ar mirror-copy
+.Cm mirror-copy
but does not exit after the initial mirroring completes.
The mirroring operation will resume as changes continue to be made to the
master.
basis.
.Pp
If the pipe is broken the command will automatically retry after sleeping
-for a short while. The time slept will be 15 seconds plus the time given
-in the
+for a short while.
+The time slept will be 15 seconds plus the time given in the
.Fl i
option.
.Pp
option may be used to disable this feature and perform an initial bulk
transfer instead.
.\" ==== version ====
-.It Ar version Ar filesystem
+.It Cm version Ar filesystem
This command returns the
.Nm HAMMER
-filesystem version for the specified
-filesystem as well as the range of versions supported in the kernel.
+file system version for the specified
+.Ar filesystem
+as well as the range of versions supported in the kernel.
The
.Fl q
option may be used to remove the summary at the end.
.\" ==== version-upgrade ====
-.It Ar version-upgrade Ar filesystem Ar version Op Ar force
+.It Cm version-upgrade Ar filesystem Ar version Op Cm force
This command upgrades the
.Nm HAMMER
-filesystem to the specified version.
-Once upgraded a filesystem may not be downgraded.
-If you wish to upgrade a filesystem to a version greater or equal to the
+.Ar filesystem
+to the specified
+.Ar version .
+Once upgraded a file system may not be downgraded.
+If you wish to upgrade a file system to a version greater or equal to the
work-in-progress version number you must specify the
-.Ar force
+.Cm force
directive.
Use of WIP versions should be relegated to testing and may require wiping
the filesystem as development progresses, even though the WIP version might
not change.
.Pp
-NOTE! This command operates on the entire
+.Em NOTE!
+This command operates on the entire
.Nm HAMMER
-filesystem and is not a per-PFS operation.
+file system and is not a per PFS operation.
All PFS's will be affected.
.Bl -tag -width indent
.It 1
.Nm HAMMER
release.
.It 2
-Work-in-progress version.
-This version is developing a new directory hash key.
+.Dx 2.3
+default version, new directory entry layout.
+This version is using a new directory hash key.
.El
.El
.\".Sh EXAMPLES
-.Sh PSEUDO FILESYSTEM (PFS) NOTES
+.Sh PSEUDO-FILESYSTEM (PFS) NOTES
The root of a PFS is not hooked into the primary
.Nm HAMMER
file system as a directory.
Instead,
.Nm HAMMER
-creates a special softlink called "@@PFS%05d" (exactly 10 characters long)
-in the primary
+creates a special softlink called
+.Ql @@PFS%05d
+(exactly 10 characters long) in the primary
.Nm HAMMER
file system.
.Nm HAMMER
contents of the link will change when the next snapshot is completed, and
so forth.
.Pp
-PFS support is currently very new and experimental.
The
.Nm
utility employs numerous safeties to reduce user foot-shooting.
The
-.Ar mirror-copy
+.Cm mirror-copy
directive requires that the target be configured as a slave and that the
-.Ar shared-uuid
+.Cm shared-uuid
field of the mirroring source and target match.
.Sh FILES
.Bl -tag -width ".It Pa <fs>/var/slaves/<name>" -compact
-.It Pa snapshots
+.It Pa <pfs>/snapshots
default per PFS snapshots directory
.It Pa <snapshots>/config
+per PFS
.Nm
-.Ar cleanup
+.Cm cleanup
configuration file
.It Pa <fs>/var/slaves/<name>
recommended slave PFS snapshots directory
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
+.Xr ssh 1 ,
.Xr undo 1 ,
.Xr HAMMER 5 ,
.Xr periodic.conf 5 ,
projects / dragonfly.git / commitdiff