Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
/ 2006-05-29 15:44:06 +0200 \ Sylvain HAU: > > HEllo, > > I have juste read the documentation concerning how DRBD works and I want further > information about it: > > I read that DRBD works as a replication tool between TWO devices (one primary > and one secondary). When an application in writting on the primary server, the > datas are immediately copied on the secondary server. > > I would like to know if the mechanism can be extended to SEVERAL secondary > servers: > is it possible when an application is conveying datas to a server (configured as > the PRIMARY) to replicate these datas to SEVERAL secondary servers? yes, though not "out-of-the-box". drbd+ (our commercial variant) among other things has some extensions for a 3node setup (e.g. normal two-node cluster plus desaster recovery site). even more than 2 secondaries: the additional complexity for handling failure cases "the right way" is probably not worth it. > Is it possible to do it in the drbd.conf file as follow: > - build the drdb.conf file as if we have just 1 primary (A) server and 1 > secondary (B) server > - add another part in the drdb.conf file with the same primary (A) server and 1 > another secondary (C) server. > In that way the datas will be copied frome the same source to 2 destinations actually you currently need to "stack" drbd. for the "shared disk semantics" case (all nodes 'Primary') we have some internal design ideas for extending drbd to support multiple nodes within one layer, and even do some sort of "smart" storage distribution, write quorum and replication level. so you could have say 7 nodes with replication level 4, three of which could crash and you'd still have access to the data. but that's handwaving at best now, and somwhere on the roadmap to drbd 9 [or 10 ;-)] -- : Lars Ellenberg Tel +43-1-8178292-0 : : LINBIT Information Technologies GmbH Fax +43-1-8178292-82 : : Schoenbrunner Str. 244, A-1120 Vienna/Europe http://www.linbit.com : __ please use the "List-Reply" function of your email client.