On Jul 14, 2010, at 9:10 AM, Peter Taps wrote: > Folks, > > This is probably a very naive question. > > Is it possible to set zfs for bi-directional synchronization of data across > two locations? I am thinking this is almost impossible. Consider two files A > and B at two different sites. There are three possible cases that require > synchronization: > > 1. A is changed. B is unchanged. > 2. B is changed. A is unchanged. > 3. A is changed. B is changed. > > While it is possible to achieve synchronization for the first two cases, case > 3 requires special merging and is almost impossible.
It is certainly not impossible, people do this every day. > I am thinking it is the same problem even at the block level. No, it is just much more difficult at the block level because blocks do not have context. Your view of A and B requires some level of context above the block level. So you must do the reconciliation at that level, not below. Hence the recommendations to use unison, hg, svn, or even OpenOffice which have the tools at the contextual level of the data to reconcile differences between two objects. > Even to achieve 1 and 2 is a bit tricky given the latency between the two > sites. Is there anything in zfs that makes it easier? Don't try to solve this problem by removing data contextual knowledge, try to solve it by increasing data context. -- richard -- Richard Elling rich...@nexenta.com +1-760-896-4422 _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
