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ZXFER(8) System Manager's Manual ZXFER(8)

NAME
zxfer -- transfer ZFS filesystems, snapshots, properties, files and di-
rectories

SYNOPSIS
zxfer [-dFnPsUv] [-k | -e] [-b | -B] {-N path/to/src | -R path/to/src}
[-m [c FMRI|pattern[ FMRI|pattern]...]]]
[-D 'progress dialog options'] [-I properties,to,ignore]
[-O user@host] [-T user@host]
[-o option1=value1,option2=value2...] [-g days] destination
zxfer {-S} [-dilpPnv] [-k | -e] [-b | -B] [-f /path/to/rsfile]
{-R/path/to/src1,path/to/src2...|-N/path/to/src1,path/to/src2...}
[-o option1=value1,option2=value2...] [-E pattern] [-L value]
[-u snapshot] destination
zxfer [-h]

Where destination is a ZFS filesystem e.g. poolname/fsname

DESCRIPTION
The zxfer utility performs two main functions. It can replicate ZFS
filesystems (including snapshots and properties) using zfs(8) send to
do the heavy lifting.

It can also transfer files and directories and the filesystems underly-
ing them using rsync(1). It will first recursively snapshot those
filesystems so that an atomic snapshot of all files and directories ex-
ists as a base. It then creates a replica of the source filesystem hi-
erarchy down to the pool level at the destination. It then transfers
the files and directories. This is desirable when we have different
snapshotting regimes on source and destination, and want to copy across
the latest contents of the filesystem(s).

Both zfs(8) send and rsync(1) use checksums/hashes to verify that the
data copied to the destination is the same data that was sent from the
source, so we have a similar degree of surety of end-to-end data in-
tegrity as the ZFS filesystem itself.

Either method allows for the properties of each filesystem to be trans-
ferred and specific properties overridden as necessary. For example,
compression, readonly, and copies are properties that are likely to be
useful to override if we are using this utility to make backups. If the
destination filesystems do not exist, zxfer will automatically create
them.

Both methods also allow the backup and restore of the original filesys-
tem properties so that if it is desirable to backup the filesystem(s)
for archival purposes using compression etc. as overrides, the original
properties may be restored without the user having to make a note of
what those original properties were.

IMPORTANT: Note that switching between these two modes is done with -S.
Depending on the mode, the workings of an option may be nonexistent,
subtly or grossly different. Don't assume an option works the exact
same way that it did with the other mode.

Note also that zxfer should be run from root, as to do anything useful
zfs(8) must also be run from root.

Note that at present, the usage of spaces in zfs(8) filesystem names is
NOT supported. There is no plan to support it without someone else do-
ing the coding or a good funding proposal coming my way.

DISCLAIMER/WARNING
You MUST read, understand and agree to the disclaimer in the BSD li-
cense before applying any of these examples or using zxfer. (See the
file "COPYING" that should have been included with this utility.) I
eat my own cooking - I use zxfer as per the examples given and as my
primary form of backup. That being said, you are strongly urged to have
a look at the script and try it out on some non-risky pools and
filesystems before using it in production. At this stage, straying too
far from the given examples will probably furnish you with the material
to submit some bug reports. Run a backup before using it and don't
shoot me if something goes wrong. This software is about beta level,
which means that if you are going to use it for backups you should
treat it more like alpha level software - i.e. trust it at your own
risk.

Modifying an example first is a good way to start using the script, as
there are some options (e.g. -d and -F in normal mode) that are in
practice always used.

SNAPSHOTS
zxfer in Normal mode as a backup/restore solution is designed to be
used hand-in-hand with a regular snapshotting regime. If there is no
regular snapshotting regime in place then the results won't be nearly
as good. zxfer would still be useful to reliably and easily copy a
pool for example, but you would be missing the main point of the pro-
gram.

OPTIONS
Common options are listed, followed by options as they function specif-
ically with zfs(8) send mode, followed by options as they work specifi-
cally to rsync(1) aka -S mode.

Please note that options with arguments (e.g. -R, -N and the like) can
not be concatenated after other options. (e.g. -vFdR source
destination will fail. You should use instead: -vFd -R source
destination ) Otherwise this will confuse getopts and zfs(8) will com-
plain that "dataset already exists".

The options are as follows:

-b Small (b)eep mode. Play a failure tune before exit with failure
so that you don't have to monitor the terminal to know when a
lengthy backup or restore finishes. (This is not as yet sup-
ported in (Open) Solaris.) To save insult being added to in-
jury, the failure beep will not play during errors that zxfer
discovers in the initialization phase, beeps will only occur if
an error has the possibility of occurring after significant
time has elapsed.

-B Large (B)eep mode. Similar to (b) but suitable for use at the
end of a script. It plays a success or failure tune before
exit. If you are executing zxfer multiple times, use -b for
everything but the last execution, for which you should use -B.

-e R(e)store property mode. This restores all filesystem proper-
ties from the backup file mentioned in the previous option.

A word of warning: In order to allow the restoration of
filesystems within the hierarchy, zxfer will begin at the level
you specify, and traverse the filesystem hierarchy back to the
pool level until it finds an appropriate .zxfer_backup_info
file or fails. It will use the first such file it comes across,
so be careful about backing up from multiple individual levels
of the same filesystem hierarchy.

-h Prints (h)elp.

-k Bac(k)up property mode. This backs up the original filesystem
property settings to a file .zxfer_backup_info.<pool_name>.
This file is located in the directory that is the mountpoint of
the parent filesystem that will contain the root filesystem you
are sending. e.g. if you are backing up zroot to be located as
per storage/backups/zroot/... the file
/storage/backups/.zxfer_backup_info.zroot would hold all the
information about the original values of the filesystem proper-
ties, and some other useful info.

This allows us to use the [-o] option freely, e.g. specifying
copies, compression etc. without having to remember what the
original options were.

A word of warning: if you intend to backup to one location and
further backup that backup to another location - sourcing the
properties to use in the final backup property file from the
property backup file in the intermediate backup is not yet sup-
ported. A workaround is to refrain from using property over-
rides in the intermediate backup; this will mean that the ulti-
mate backup will be able to store the correct properties of the
original.

-n Dry ru(n) mode. Prints out the commands that would otherwise
execute but does not execute them. This may not work in all
circumstances as it may expect the existence of filesystems
etc. that won't be created.

-o (o)verride property mode. Property overrides are specified with
commas to separate.

e.g. -o property1=value1,property2=value2... For example, -o
compression=lzjb will cause all destination filesystems to be
set to lzjb compression. If using recursive mode, only the root
filesystem will be set, and all other filesystems will inherit
from this. Note that this option will also override any values
that would otherwise be set by "-P". Invoking this option will
also create the destination filesystem(s) if they do not al-
ready exist.

-P Transfer (P)roperty mode. This causes the destination to have
properties explicitly set (i.e. with property sources as local)
to exactly the same properties as the source. If the destina-
tion filesystems do not exist, they will be created with the
correct properties.

If using recursive modes, child filesystems have property
sources (as in, the fourth column of # zfs get all
pool/filesystem ) that are made either local, (if the source is
local) or inherited (if the source is default or inherited) as
per the source filesystem. Note that inherited behaves in a
similar manner to default. If you were to set a given property
of the parent of a child filesystem, the child would have that
same property's source listed as "inherited from..." whether
that child property source had been default or inherited.

There are several properties that must be set (using zfs
create) at filesystem creation time. These are:
casesensitivity, normalization, jailed, utf8only. If you are
trying to replicate such a filesystem where one of these prop-
erties is different from source to destination, destroy the
destination filesystems before you begin otherwise the utility
will fail with an error.

There are several other properties that may not be technically
readonly but it was judged that it would not make sense to try
and transfer them. They are: type, creation, used, available,
referenced, compressratio, mounted, version, primarycache,
secondarycache, usedbysnapshots, usedbydataset, usedbychildren,
usedbyrefreservation, version, volsize, mountpoint. There are
several properties in FreeBSD 8.2 that are not supported and
hence will not be transferred via zxfer, they are: idevices,
aclmode, aclinherit, nbmand, shareiscsi, vscan, xattr. If us-
ing -S, all filesystems in the pools containing the source di-
rectories/files will be created on the destination if they
aren't in existence already, whether they are to hold files/di-
rectories or not.

-S rsync(1) mode. If -S is specified, rsync(1) mode is triggered.
If -S is absent, zfs(8) send mode is in effect. Several options
have different effects depending on whether -S is present or
not. Consult the relevant option section before using.

It is also possible to transfer to readonly destination
filesystems, but this is only supported if either [-o] or [-P]
is enabled.

-v (v)erbose mode.

Normal | zfs send/receive mode
(i.e. -S is absent)

-c A space delimited list of SMF services in quotes to be tem-
porarily disabled before unmounting the source, then re-enable
after changing the mountpoint of the destination. Requires -m.

-d (d)elete snapshots on the destination that are absent on the
source. This may be necessary to function properly anyway, in a
similar fashion to

-D zxfer will pipe zfs(8) send through the indicated command and
parameters, to create a progress bar. A number of macros will
be replaced with values before the command is executed:

%%size%%
Will be replaced with the estimated size of the snapshot.

%%title%%
Will be replaced with the name of the source dataset@snap-
shot.

Example:

zxfer -O user@host -D 'bar -s %%size%%' -R source destination
[-F]. This will occur if you are using zxfer for routine back-
ups and in the interim, culling snapshots on the source. The
snapshot corresponding to the most recent snapshot on the des-
tination often gets deleted on the source. Any snapshots on the
destination more recent than the most recent common snapshot
must be deleted for zfs send to work.

-g (g)randfather protection. Specify a number of days old (rela-
tive to the system date) at and above which snapshots on the
destination won't be deleted. For use with [-d]. This allows a
safeguard to protect the "grandfathers" in a Grandfather-Fa-
ther-Son (GFS) snapshot collection on a destination. Grandfa-
thers (as defined by zxfer) are the snapshots that never get
deleted (often yearly, half yearly or quarterly snapshots).

Note that for this to work properly, you must set [-g] so that
it does not inadvertently protect the "fathers" which will be
deleted on the source by your snapshot management tool, and
hence will need to be deleted on the destination. If you go a
long time between backups with an otherwise well set [-g], you
may have fathers on the destination that are the age of grand-
fathers and so you will need to either relax the number of days
provided for, or manually delete those fathers.

For example, specifying -g 375 should protect snapshots as old
or older than 375 days, which could be useful where grandfa-
thers are yearly and monthly fathers are kept for a period of a
year or less. This gives us 9 days of grace period to make a
backup without throwing an error, but do note that during this
grace period grandfathers less than 375 days old are not pro-
tected.

-I properties,to,ignore
Do not copy this comma separated list of properties when per-
forming replication. Useful for skipping properties like quo-
tas that can interfere with replication, or properties that are
not supported on the destination.

-m After sending all snapshots, (m)igrate the source to the desti-
nation filesystem by unmounting the source filesystem and
changing the new filesystem's mountpoint to that of the source.
This option includes -s. It also includes -P. Note that zxfer
does not prevent you from migrating a default mountpoint (e.g.
pool/filesystem) to something that will be potentially confus-
ing, so be sure that this is what you want before executing.

Note also that [-O] and [-T] (i.e. remote transfers) are not
supported with this option enabled.

-N Replicate the listed filesystem. Note the provisos listed above
in [-R]. It works similarly but is (N)ot recursive. e.g.
specifying -N tank/tmp will transfer only tank/tmp.

-O Specify an (O)rigin user@host. This allows transfers FROM a re-
mote host via ssh. e.g. Whatever filesystems you specify as
the source are taken to exist on that remote host.

For this to work, you must have a working ssh connection from
your local machine to the remote host, using public key based
authentication (so that you won't have to keep entering a pass-
word every time a command is sent over ssh). You must have
zxfer on your local machine. The remote host must support
zfs(1), and so does your local machine if [-T] is not also
used.

This option has been somewhat tested in FreeBSD 8.2 and Solaris
11 Express and appears to be working. (Consider it alpha
level.) These are the only operating systems that it has been
tested on, and possibly/probably won't work on others.

Note also that transferring between different operating systems
and even different versions of the same operating system (e.g.
FreeBSD 8.1 and 8.2) has not been tested and will probably fail
or give unexpected results. As zfs(1), has been developed, new
properties have come into being, and those properties have ei-
ther been supported in FreeBSD or they haven't. So it is diffi-
cult to know what a user would like to have such properties be
when they are copied from one OS (or version) to another. At
least between OS versions, you are advised to use the same OS
and zpool and zfs version from source to destination. It's not
likely I will test this thoroughly in the near future, as it
requires an estimated n^2 number of tested transfers, where n
is the number of operating system variations to support. You
are welcome to try it though, and report bugs back to me.

Note that if at all possible, do not try and be clever and run
zxfer with both an origin and a target host. While this may
work, the transfer will be piped from the remote origin to the
local machine and from there to the remote target machine,
which will be slow as it is not a direct path.

The syntax for this command is -O user@remote_host.

e.g. -O root@192.168.0.1

Please note that if you are using Solaris, you will most likely
need to use "pfexec" (similar to sudo) and have a suitably
privileged user. Copy the quotes and spacing exactly:

e.g. -O "user1@192.168.0.1 pfexec"

The reason this works is because the commands that are related
to reading/writing/modifying data will be prefaced with in nor-
mal circumstances:

ssh root@192.168.0.1 command ...

So with Solaris, specifying the pfexec at the end results in:

ssh user1@192.168.0.1 pfexec command ...

-R (R)ecursively replicate all filesystems under the specified
source. If not specifying [-S], you must invoke one and only
one of either [-R] or [-N]. Note that if you enable this op-
tion, you must specify only one filesystem, and that it starts
without a "/". e.g. specifying -R tank/tmp will transfer
tank/tmp, tank/tmp/foo, tank/tmp/foo/bar etc.

Also note that a trailing slash on the source filesystem has a
similar effect as it has in cp(1). This would primarily be
used in restoring filesystems, especially pools. See Ex3.

-s Make a (s)napshot of the source before replication. Note that
you might want to transfer a current snapshot at the end of a
transfer, as the initial transfer might take a long time. This
would leave you with an old snapshot on the destination. To do
this you will need to execute your command again at the end,
and ensure that a current snapshot is taken before or during
the second execution. e.g. use this option to ensure that a
relatively current snapshot exists, create it manually, or wait
until your own snapshotting regime does the job for you (if you
have one).

-T Specify a (T)arget user@host. This allows transfers TO a remote
host via ssh. e.g. Whatever filesystem you specify as the des-
tination will be where the source filesystems will be sent.

See the section on [-O] for notes, usage advice and warnings,
as this option is very similar in operation.

The syntax for this command is -T user@remote_host. e.g. -T
root@192.168.1.2

Again, please note that if you are using Solaris, you will most
likely need to use "pfexec" (similar to sudo) and have a suit-
ably privileged user. Copy the quotes and spacing exactly:

e.g. -T "user1@192.168.0.1 pfexec"

-U Skip replicating any properties that are not supported by the
destination. Before replication begins, a list of supported
properties is fetched from the destination and any properties
not on that list are removed from the list of properties to be
replicated. This allows replicating from newer versions of
OpenZFS to older versions.

Rsync mode
(i.e. -S is specified)

-d (d)elete files on the destination that do not exist on the
source. This is equivalent to rsync --del.

-E Pass (E)xclude patterns to rsync(1). e.g. If you want to spec-
ify "--exclude=/boot/zfs/zpool.cache" when rsync(1) is called,
then use "-E /boot/zfs/zpool.cache". You can specify this op-
tion as many times as you like, and it will pass each exclude
pattern to rsync(1). My understanding of how to get this to
work is to specify the exclude as a continuation of the
filesystem mountpoint on which the file/directory is stored.
e.g. with "/boot/zfs/zpool.cache" it works because the mount-
point of zroot is effectively "/".

-f Specify a (f)ile that contains a list of options to feed to
rsync. In this event, no other options will be given to rsync.
(If this option is not enabled, the default options given to
rsync are -clptgoD --inplace --relative -H --numeric-ids. )

It has been suggested that it might be more convenient to be
able to specify custom options to rsync by means of a switch
and the options in quotes or some other delimiting character.
If there is enough feedback I will consider implementing this
option.

-i (i)nclude directories corresponding to ZFS filesystem mount-
points on the destination when transferring. The default is to
exclude them, since the destination may correspond to a
filesystem from another pool mounted there, which has its own
data and would be restored independently.

-l Treat (l)egacy mountpoints as being equal to "/". If this is
not enabled, zxfer will fail with an error when it encounters a
legacy mountpoint.

-L Specify how many (L)evels deep in the source filesystem tree
the filesystem that was originally a backed up pool now lies.
Most likely, this will only need to be used in the event of a
restore, as the default level (zero) will create filesystems
from the pool level on down at the target. e.g. if we are try-
ing to restore /storage/backups/zroot/tmp/stuff.txt which was
originally in a pool named zroot, and wished it to end up where
it originally came from (e.g. at zroot/tmp/stuff.txt ) we would
indicate with -L 2 that the original pool is located 2 levels
deep on the source. If we did not specify that option, we would
end up with the file transferred to
/zroot/backups/zroot/tmp/stuff.txt, which is not what is
wanted.

-N Replicate the listed director(y | ies) or file(s). Note the
provisos listed above in [-R]. It works similarly but is not
recursive. e.g. specifying -N /tmp will transfer only /tmp.

-p (p)ersist through rsync(1) errors. This saves having to feed
directories individually to zxfer, if we expect rsync to return
an error at some point (e.g. when it tries to overwrite it-
self).

-R (R)ecursively replicate all directories and files under the
specified source(s). If specifying [-S], you must invoke at
least one or both of either [-R] or [-N]. The idea is that
this utility makes an atomic clone of the filesystems you will
need to get your files/directories from, and you can use rsync
to decide what to transfer within a given pool.

Note that if you enable this option, you can specify as many
directories as you like, separated by commas (with no spaces).
Directories must start with a / and may or may not end with a
/. Read the rsync(1) man page to get the gist of how that
works. e.g. specifying -R /tmp will transfer /tmp, /tmp/foo,
/tmp/foo/bar etc.

Note also that zxfer will only transfer the contents of the di-
rectory "/" if [-l] is invoked, "/" is mounted as legacy, and
it will only transfer across those files and directories be-
longing to the same ZFS filesystem as / belongs to.

Another action not supported is recursively transferring a di-
rectory that contains directories that are in fact filesystems
from other pools, or in fact any included directories where the
filesystem mountpoints diverge from what ZFS would assign by
default.

-u (u)se an already existing snapshot as the source to transfer
from. You should first check that this snapshot exists on all
the filesystems that house the files and directories to be used
in the transfer. This gives us the option of restoring
files/directories without having to roll back.

EXAMPLES
Note that some of these example commands are lengthy, so be sure to fix
the line wrapping appropriately. Also if you wonder why zxfer isn't
transferring anything, please read the section titled SNAPSHOTS.

Ex1 - Backup a pool (including snapshots and properties)
We have a pool called storage and we want to back it up to
backup01/pools, along with all its snapshots. Grandfather snapshots are
yearly, fathers are monthly and are deleted after 365 days. The resul-
tant filesystem hierarchy should look like so:
• backup01/pools/storage
• backup01/pools/storage/home
• backup01/pools/storage/back
• etc.
To back this up while:
• [-g] protecting (grandfather) snapshots older than 375 days
• [-P] copying across the properties of each filesystem
• [-k] storing the original filesystem properties in the file
backup01/pools/.zxfer_backup_info.storage
• [-F] forcing a rollback of destination to the most recent
snapshot. Given even mounting the filesystem will cause a
change and hence cause zfs receive to fail with an error, en-
abling this is the way to go. Otherwise you would be modify-
ing(!) a backup, wanting to keep the changes you are mak-
ing(!?) and also wanting to copy more stuff to the backup
(hence it's still being used as a backup)... well if that's
what you want then don't use this option.
• [-d] deleting stale snapshots that don't exist on the source
(e.g. if using a snapshot management script such as
zfs-snapshot-mgmt(8), snapshots are regularly taken and regu-
larly deleted to leave a range of frequencies of snapshots at
different vintages. If you are regularly backing up to an-
other pool which is stored off-site as is highly recommended,
you may want to delete the stale snapshots on the backup pool
without having to manage the snapshots there too. This is es-
pecially true for those pools that are usually not connected
to a machine, e.g. if you are using HDD as backup media. Note
that zfs send will also refuse to work if you have newer
snapshots on destination than the most recent common snapshot
on both, so it's easier to just enable it.)
• [-v] seeing lots of output (verbose)
• [-R] copying the source filesystem recursively
use the following command:

zxfer -dFkPv -g 375 -R storage backup01/pools

Note that this same command will work for both the initial replication
and subsequent replications (which are potentially much faster due to
incremental transfers being used). Also note that if you don't have any
snapshots on the source, nothing will be transferred. You can create a
snapshot for this very occasion by adding the -s option.

Ex2 - Backup pool to HDD
Using HDDs as backup media was in large part a motivation for writing
this utility. (Using an e-SATA dock is particularly convenient). The
source and destination are the same as Ex1.

We will want to increase the number of copies to at least 2 or more so
that we have some protection against bad sectors. We won't have protec-
tion against a HDD crash so use more than one HDD if you are doing this
(mirrored or otherwise). We may also want to override the compression
to make up for the multiplication in disk usage by the number of
copies. Here is the command:

zxfer -dFkPv -o copies=2,compression=lzjb -R storage backup01/pools

Ex3 - Restore a pool
To restore the pools we have backed up in Examples 1 and 2, we would
first make sure that there is a new pool named storage to copy the
backup to. Then we would issue the following command:

zxfer -deFPv -R backup01/pools/storage/ storage

Note that the trailing slash enables us to copy the zroot filesystem
directly to the pool level, and then the child filesystems below that,
which is where we want them. If the pool name is to be changed, the
command becomes:

zxfer -deFPv -R backup01/pools/storage/ newpoolname

Ex4 - Backup a filesystem
We might want to just backup a filesystem within a pool. That is easily
done:

zxfer -dFkPv -N storage/home backup01/filesystems

The resulting filesystem will be backup01/filesystems/home. This exam-
ple will only replicate that exact filesystem (i.e. it is non-recur-
sive). If we wanted to recursively transfer all filesystems under
storage/home at the same time we could do so by changing the [-N] to an
[-R].

Ex5 - Restore a filesystem
To restore the filesystem backed up in Ex4, we would do so using the
following command:

zxfer -deFPv -N backup01/filesystem/home storage

Ex6 - Recursive directory backup
We might want to backup a directory within a pool, using rsync to do
the heavy lifting, while also making a backup of the properties of the
filesystems transferred. Transferring via [-S] will allow us to have
different snapshotting regimes on source and destination coexisting
happily.

zxfer -SkPv -R /storage/home backup01/rsbacks

The resulting filesystem structure will look like:
backup01/rsbacks/storage/home.

If we wanted to non-recursively transfer that directory we would just
change the [-R] to an [-N].

Ex7 - Recursive directory restore
To restore the directory backed up in Ex6, we would do so using the
following command:

zxfer -SePv -L 2 -N /backup01/rsbacks/storage/home storage

Note that we had to specify a drop back of 2 levels of filesystems, so
that zxfer would know that the pool level is not backup01 but storage.
Specifying -L of 1 would indicate that the pool level was rsbacks,
which it was not. Leaving out [-L] would be equivalent to L=0, or spec-
ifying that the pool level was backup01.

Note also that this will re-create all the original filesystems that
existed on the pool "storage" with their original properties, if they
have since been deleted. If those filesystems still exist, zxfer will
ensure that each such filesystem have the properties they originally
had. Note that if those filesystems still exist, no data will be
changed other than what you have specified to be rsynced across.

If you wish to not have filesystems created or properties set (just the
files/directories you want rsynced), just forego [-P] and [-o]. Note
that this will only work on filesystems that are writable.

Ex8 - Backup FreeBSD 8.2 root mirror
This will make a recursive snapshot of the root mirror, create similar
filesystems on the pool storage, transfer the properties over, rsync(1)
across the directories and files needed to restore the system, and de-
stroy the snapshots when done. To see how to do this in more detail,
check out the zxfer wiki.

zxfer -SPkld -R
/bin,/boot,/compat,/etc,/lib,/libexec,/rescue,/root,/sbin,/tmp,/usr,/var,/vshare
-N /.cshrc,/.profile storage/zr_backup

The resulting filesystem structure will look something like:
storage/zr_backup/zroot storage/zr_backup/zroot/usr
storage/zr_backup/zroot/var etc.

Ex9 - Restore FreeBSD 8.2 root mirror
To restore the config files backed up in Ex8, we would do so using the
following command after installing the system, installing zxfer and
booting up in the system. This uses the snapshot
auto-2010-11-14_14.00. Note that for this to work properly /var/empty
must be set to mutable. Also, the flag "schg" must be turned off to
transfer properly. For the full sequence of commands, see the zxfer
wiki. Here is the command for the zxfer part of the procedure (note you
will need to add any directories of your creation kept on your zroot
e.g. "vshare"):

zxfer -SpldBv -E /boot/zfs/zpool.cache -u auto-2010-11-14_14.00 -L 2 -N
$zrootdir/.cshrc,$zrootdir/.profile -R
$zrootdir/bin,$zrootdir/boot,$zrootdir/compat,$zrootdir/etc,$zrootdir/lib,$zrootdir/libexec,$zrootdir/rescue,$zrootdir/root,$zrootdir/sbin,$zrootdir/tmp,$zrootdir/usr,$zrootdir/var,$zrootdir/vshare
zroot

Ex10 - Migrate a filesystem
We might want to migrate a filesystem (including properties). Note
that this is only allowable when the original mountpoint is not the de-
fault (i.e. pool/filesystem). In the following example, the new
filesystem will be located in new_pool/location/fs. If the old mount-
point was /path/to/old_fs then that will be the mountpoint of the new
filesystem.

zxfer -PmFdv -N original_pool/fs new_pool/location

Ex11 - Compress a filesystem
If we want to compress a filesystem, it is not enough to simply set a
compression setting of some sort on that filesystem. This will only
cause new files to be compressed. If we want to compress a filesystem,
what we would want to do is to transfer it to another location (where
compression is enabled).

zxfer -PmFdv -o compression=gzip -N original_pool/fs new_pool/location

Ex12 - Compress a filesystem...
- and store it in the original location. This is probably what you
want to do instead of example 11. Usually what we want to do when we
want to compress a filesystem - it is already in the location we want
it to be, just we haven't realized we wanted it compressed at the time.
Or maybe we want to do something similar to compression, like dedup,
and it was not supported at the time we created the filesystem. So it
is not enough to have the filesystem compressed in a new location, we
want it in the original location.

If so, we will need to migrate the filesystem. Then, if necessary, we
would need to upgrade the original pool to ensure that the new filesys-
tem can do what it is we want it to do (e.g. dedup perhaps), and then
transfer it back. Here are the steps.

1. Ensure you have set aside a time where nothing will be reading or
writing to the filesystem(s) in question. If you are performing this
operation on a system filesystem (e.g. something like zroot/usr) then
ensure that you are performing these operations from a recovery disk
(e.g. Fixit # in FreeBSD). Also it is a very good idea to ensure that
you have made backups of the filesystems you are going to perform this
operation on.

2. Migrate the filesystems to a new location. e.g.

zxfer -PmFdv -N original_pool/fs new_pool/location

3. Triple check that the new filesystems are as they should be. Be
very, very, very careful here. It is a good idea to have made a backup
before doing this next step. In fact, it's probably worth practicing on
a system you don't care about first. And do not, repeat do not, blame
me if something goes wrong.

4. Destroy the original filesystem. e.g.

zfs destroy original_pool/fs

5. Ensure that the original pool is upgraded to do what you want it to
do (e.g. dedup perhaps, though you will need to change the option set-
ting appropriately).

6. Migrate the filesystem back, but with the overrides you want. e.g.

zxfer -PmFdv -o compression=gzip -N new_pool/location/fs original_pool

Ex13 - Backup a pool to a remote host
Notice this is the same as in Ex2 with the exception of option [-T],
and uses the same options which have been explained in that example.
Note that if you use Solaris you will most likely need to specify
pfexec (refer to the [-O] section). Here is the command:

zxfer -dFkPv -o copies=2,compression=lzjb -T root@192.168.123.1 -R
storage backup01/pools

Ex14 - Restore a pool from a remote host
Use the following command, assuming that you are restoring from a situ-
ation as in Ex13. Again, if using Solaris refer to [-O].

zxfer -deFPv -O root@192.168.123.1 -R backup01/pools/storage/ storage

EXIT VALUES
zxfer exits 0 on success, 1 on an error and 2 if a command line option
is incorrect.

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