comment below...
Uwe Dippel wrote:
Dear Richard,
> > Could it be that you are looking for the zfs clone subcommand?
>
> I'll have to look into it !
I *did* look into it.
man zfs, /clone. This is what I read:
Clones
A clone is a writable volume or file system whose initial
contents are the same as another dataset. As with snapshots, creating a
clone is nearly instantaneous, and
initially consumes no additional space.
Clones can only be created from a snapshot. When a snapshot is
cloned, it creates an implicit dependency between the parent and child.
Even though the clone is created
somewhere else in the dataset hierarchy, the original snapshot
cannot be destroyed as long as a clone exists. The "origin" property
exposes this dependency, and the
destroy command lists any such dependencies, if they exist.
The clone parent-child dependency relationship can be reversed
by using the "promote" subcommand. This causes the "origin" file system
to become a clone of the speci-
fied file system, which makes it possible to destroy the file
system that the clone was created from.
...
zfs clone snapshot filesystem|volume
Creates a clone of the given snapshot. See the "Clones"
section for details. The target dataset can be located anywhere in the
ZFS hierarchy, and is created as the
same type as the original.
...
Example 9 Creating a ZFS Clone
The following command creates a writable file system whose
initial contents are the same as " pool/home/[EMAIL PROTECTED]".
# zfs clone pool/home/[EMAIL PROTECTED] pool/clone
Richard, I can read and usually understand Shakespeare, though my mother
tongue is not English. And I've been in computers for 25 years, but this
is definitively above my head.
Yeah, I know what you mean. And I don't think that you wanted to clone
when a simple copy would suffice.
In order to understand clones, you need to understand snapshots. In my
mind a clone is a writable snapshot, similar to a fork in source code
management. This is not what you currently need.
The latter comes closest to be understood, but does not address my
persistent problem of me having slices on other disks; not a new pool
within my file system.
zpools are composed of devices.
zfs file systems are created in zpools.
Historically, a file system was created on one device and there was only
one file system per device. If you don't understand this simple change,
then the rest gets very confusing.
To me it currently looks like a 'dead' invention; like so many so great
ideas in the history of mankind.
Serious, I saw the flash presentation, knew ZFS is *the* filesystem for
at least as long as I live !
On the other hand, it needs a 'handle'; it needs to solve legacy
problems. To me, the worst decision taken until here, is, that we cannot
associate an arbitrary disk partition or slice - though formatted as ZFS
- readily with a mount point in our systems; do something that we
control; and relinquish the association.
See previous point.
In order to be accepted on a breadth, IMHO a new filesystem - as much as
it shines - can only succeed if it offers a transition from what we
system admins have been doing all along, and adds all those phantastic
items.
Look, I was kind of feeling bad and stupid for my initial post. Because
I'd myself answer RTFM if someone asked this in a list for BSD or Linux.
And the desire is so straightforward:
- replicating an existing, 'live' file system on another drive, any
other drive
tar, cpio, rsync, rdist, cp, pax, zfs send/receive,... take your pick.
- associate (mount) any slice from an arbitrary other drive to a branch
in my file system
Perhaps you are getting confused over the default mount point for ZFS
file systems? You can set a specific mount point for each ZFS file system
as a "mountpoint" property. There is an example of this in the zfs(1m)
man page:
EXAMPLES
Example 1 Creating a ZFS File System Hierarchy
The following commands create a file system named
"pool/home" and a file system named "pool/home/bob". The
mount point "/export/home" is set for the parent file sys-
tem, and automatically inherited by the child file system.
# zfs create pool/home
# zfs set mountpoint=/export/home pool/home
# zfs create pool/home/bob
What you end up with in this example is:
ZFS file system "pool/home" mounted as "/export/home" (rather than
the default "/pool/home")
ZFS file system "pool/home/bob" mounted as "/export/home/bob"
IMHO, this isn't clear from the example :-(
-- richard
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
