Hello David, we have opened a Blueprint for this idea. We'll concentrate on it as soon as we released a stable version -- and I'm sure we'll get back to you and ask you for advice :-)
Cheers, Philipp On Sun, Jun 5, 2011 at 1:14 AM, David TAILLANDIER <[email protected]> wrote: > > >> I apologize for my late e-mail > > Not a problem. I just emailed you in case this idea could be of any use. > > > > >> If I have 3 different storages, and I'd like to store 10GB, I would >> create parity files for these 10GB with ~34% redundancy (--> 10GB + 3,4 >> GB parity files). I would then split the 10GB in 3,33GB parts and upload >> them to the three storages (together with one third of the parity >> files), i.e. each repository would get 3,33+3,4/3 = 4,46 GB of data. If >> now one of the storages fails, I can still restore 100% of the data. Did >> I get that right? > > In overall you're right. But you miss something very important: the real > potential is the fact you can set the loss percentage as you want. > With 3 storage locations you can set it to 0% or 33% or to 66% (other values > are not sensible for 3). > 0% = usual way to store things > 33% = sort of RAID5 > 66% = you can loss 2 storages locations without having problems (at the cost > of more transfert, time, money, etc) > > Let's say you have 10 storage locations, you can set the acceptable loss > from 0% to 90% by 10% steps. > Can you imagine to loss more than 2 storage at the same time ? If not, then > you have 20% acceptable loss. Set it to 30% to be sure. This is nearly > indestrutable. > > The hard thing is: > - not every storage locations are of equal size > - the user don't want the same amount of security for every data > - with many storage locations, this is not mandatory to save everything > into every location > Each of those can be optional. But if you can deal with this, you're the > king :-) > > Storage locations of equal size: > solution 1: use the smallest size for all > solution 2: compute the resulting loss factor for each size (ideal) > > The user don't want equal security for all: > solution 1: don't let him set different levels for different datas (but > what if he change his mind ?) > solution 2: ... I don't know your software enought for that :-) > > This is not mandatory to store everything everywhere (usefull with tons of > storage locations). > This is totaly dependant of your algorithm, so nothing can be said now. > > > > Feel free to ask me anything. But as I'm not a good programmer, I think I > gave my max already. > > > -- Mailing list: https://launchpad.net/~syncany-team Post to : [email protected] Unsubscribe : https://launchpad.net/~syncany-team More help : https://help.launchpad.net/ListHelp
