| Yeah.....which does not stop AFS from choking when quorum goes away. Oh yeah? Find me another system where you can crash even more than one server and still keep the system functioning decently... ;-) | I hope that the pts changes will make it do what I need it to; We've | been waiting for R/O access out of quorum since 1993. Without R/O | access out of quorum, AFS is really unsuitable for widely distributed | production environments. I dont think that quorum is the main issue about wide-area access, but that is neither here nor there. The point is anything weaker than transactional semantics when using replication for such metadata is known to be a root cause of `bad' behaviour in almost all distributed systems. If you weaken it (for example, by giving out info outside of quorum), you will have much more hairy problems that just WAN access. | Your statement that the vlserver will not work the same way worries me; | what does that mean for clients of a machine (assume it's running all | services) that's out of quorum? Will they be able to reboot and still | get r/o AFS space? I am not certain what you mean by "clients of a machine that is out of quorum". By definition, a machine outside quorum has no clients. I suppose what you meant was "what if a client has no access to vlservers that _are_ in quorum?" Well, given that and your reboot in between, such a client is out of luck. Normally, a client caches everything, so if it has been up for a while, the (temporary) lack of access to a quorum of the vlservers is rarely noticed. On reboot however, the meta-data cache is purged. | | The manpages say: | | when the information in the VLDB is | inaccessible, the Cache Manager cannot retrieve files, even | if the File Server processes are working properly. | | Does this mean that AFS will NOT work out of quorum for read/only | files at 3.4?? I think there is some confusion here about what read-only data we are talking about. There is the data in the fileservers (user-data) and data in the database servers (meta-data). User-data is either r/w or r/o. Meta-data is always r/w. Fileservers will always give out user-data (r/w or r/o), whether or not the database servers are in quorum. It is a function of the client whether it has access to a vlserver that is in quorum to be able to find a suitable fileserver. What I was talking about was the conditions under which database-servers allow read-only transactions on the r/w metadata to complete. To read meta-data, in the case of the pt and ka servers, one need not contact a member of the quorum subset. (to modify meta-data, one has to be able to contact a database server that is in quorum, kadb, budb, ptdb and vldb alike).
