Matthew Ahrens wrote:
On Tue, May 09, 2006 at 01:33:33PM -0700, Darren Reed wrote:
Eric Schrock wrote:
...
Asynchronous remote replication can be done today with 'zfs send' and
zfs receive', though it needs some more work to be truly useful. It has
the properties that it doesn't tax local activity, but your data will be
slightly out of sync (depending on how often you sync your data,
preferably a few minutes
Is it possible to add "tail -f" like properties to 'zfs send'?
I suppose what I'm thinking of for 'zfs send -f' would be to send
down all of the transactions that update a ZFS data set, both the
metadata and the data.
'zfs send' always sends all the changes, including metadata and data.
The catch here would be to start the 'zfs send -f' at the same time
as the filesystem came online so that there weren't any transactional
gaps.
You can always simply run 'zfs snapshot; zfs send -i ... | ssh ...' in a
loop. This is an implementation of best-effort remote replication.
Perhaps you're looking for a more real-time remote replication. See:
5036182 want remote replication (intent-log based)
Yes, I think this is what I was thinking of.
If I could add a vote to it via opensolaris.org, I would :)
Would it be possible to specify more than 1 remote destination
for a single replication?
Or could you chain together replication, so that I have:
hosta# zfs send -f | rsh hostb zfs receive -f
hostb# zfs send -f | rsh hostc zfs receive -f
The second would feed of the intent-log updates from the input
of the first, allowing for cascaded remote replication.
Another possible remote replication implementation would allow the
administrator to put a bound on how much the remote side can be out of
date (eg. by an amount of time, or amount of modified data). This could
be implemented by using 'zfs send -i', with some hooks to stall changes
to the filesystem if the 'zfs send -i' gets too far behind.
That's a great idea too :)
Darren
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