Hello, We have one cell covering two sites. The WAN bandwidth between the two sites is relatively low, so we use volume replication to speed up the access.
Those replicated volumes are often large in size. So replication to the remote site is an operation whose cost cannot be neglected. Now with RW volumes at site A and their RO replication on servers at site B, we want to bring up a new file server at site B to balance the load. In other words we would like to "offload" a majority of the RO volumes from one server to a different server at Site B, without touching their RW masters at Site A. The standard way to do this is through "vos addsite" and "vos release" to create new RO copies on the new server at site B. When we try this it seems that the "vos release" always initiates a fresh full volume of data transfer from the RW servers at site A to the new server at site B, even though there are RO copies at site B on other servers. I wonder if there is a way to directly transfer those RO volumes btw servers at site B, without breaking the data integrity among the RO sites or affecting the atomicity of "vos release". Or maybe a more greedy way to ask the question is: Is it possible to make the data transfer part of "vos release" smarter, by allowing it to select the closest path to copy data btw file servers, according to a network distance either detected by itself, or provided by the administrator? For example, once it is found that no change has been made to the RW volume since the last release, a "vos release" to a new site will search all the RO copies in the VLDB, find the closest RO site to the new server, and initiate data transfer from there, instead of from the RW site? Even if the RW volume has been changed, maybe it would still be much cheaper to copy the existing RO volume from a closest site first, and then broadcast the incremental changes from the RW site? Thanks. Ximeng (Simon) Guan Royole Corporation
