On 24 Jan 2014, at 07:48, Harald Barth <h...@kth.se> wrote: > You are completely right if one must talk to that server. But I think > that AFS/RX sometimes hangs to loooooong on waiting for one server > instead of trying the next one. For example for questions that could > be answered by any VLDB. I'm thinking of operation like group > membership and volume location.
I have long thought that we should be using multi for vldb lookups, specifically to avoid the problems with down database servers. The problem is that doing so may cause issues for sites that have multiple dbservers for scalability, rather than redundancy. Instead of each dbserver seeing a third (or a quarter, or ...) of requests it will see them all. Even if the client aborts the remaining calls when it receives the first response, the likelihood is that the other servers will already have received, and responded to, the request. There are ways we could be more intelligent (for example measuring the normal RTT of an RPC to the current server, and only doing a multi if that is succeeded) But we would have to be very careful that this wouldn't amplify a congestive collapse. Cheers, Simon_______________________________________________ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info
