> ------------ Původní zpráva ------------ > Od: Fajar A. Nugraha <l...@fajar.net> > Předmět: Re: Re: Two way mirror in BRTFS > Datum: 30.12.2011 15:34:02 > ---------------------------------------- > 2011/12/30 Jaromir Zdrazil <jaromir.zdra...@email.cz>: > >> > Just to add, I would like to see a two way mirror solution, but if it > >> > will > not > >> work now/is not implemnted yet, I would propably choose between drbd in > >> asynchronous mode or make a some kind if "incremental" snapshot to a remote > >> mapped disk (I do not know yet, if brtfs support it) - it means have one > >> shapshop and let's say have a daily incremental update of this snapshot. > >> > >> You mean like "zfs send -i"? If yes, why not just use zfs? There's > >> zfsonlinux project, with easy-to-install ppa for ubuntu. Or you could > >> compile it manually. > >> > > Thank you for your suggestion. As I know, there is not everything ported > > yet, > and one of the missing important features I plan to use is to crypt fs. > > correct. But btrfs doesn't do encryption as well.
I thought it does. Hmm, don't know why ;O) > And if you're thinking of using luks/dm-crupt to provide encryption > for btrfs, there's nothing preventing you to use the same thing with > zfs. > > > And if I am not mistaken, current version does not yet support a mountable > filesystem. > > You're mistaken :) With some extra work, you can even use it as root: > - http://zfsonlinux.org/example-zpl.html > - > https://github.com/dajhorn/pkg-zfs/wiki/HOWTO-install-Ubuntu-to-a-Native-ZFS-Root-Filesystem > It seems I trust the web pages too much - in http://zfsonlinux.org/ is written that it does not ;O)) otherwise I would be using it already. > >> > > >> > How would you do it? > >> > >> If you DO mean zfs-send-like-functionality, then you should ask about > >> "btrfs send and receive", not "two way mirror" (which is not an > >> accurate way to describe what you want). Also, send/receive ability > >> does not mean it can act as two-way mirror. It CAN be an alternative > >> to drbd async though. > > > > If I understand it correctly, the diff between send and receive and two way > mirror is that one is synchronous and the other is not (sends the signal that > the file have been succesfully written after all/one instance have been > succesfully written). > > Maybe you can explain it a bit more. > > Two way: A replicates changes to B, and B can replicate it's own changes to A > One way: A replicates changes to B, but B can not replicate it's own > changes to A > Of course. > While drbd only supports synchronous mode for active-active setup, the > generic "two way replication" does not have to be so. Also, just > because something is synchronous does not automatically mean it > supports two-way replication. > Correct. > Either way, neither zfs or the (planned) btrfs send/receive supports > two-way/active-active setup. Both should (or will) work just fine for > one-way replication. > That is what I needed to know! Thank you very much! Jaromir > -- > Fajar > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
