CODA 2 PROJECT FILE UPDATE

Note that while a client is in its EMULATION state, it may still be able to contact servers that manage other volumes. This means that all file requests will be directly serviced using the locally cached copy of the file. While in this state, the client can contact the server and issue file requests to perform its work, simultaneously, it will also attempt to keep its cache filled with useful data EMULATION AVSG=0 behavior of a server for the volume is emulated on the clientвЂ™s machine. HOARDING normal state of a client Client connected to (at least) one server that contains a copy of the volume.

An interesting aspect of Coda that needs further explanation is how a client can continue to operate while being disconnected, even if disconnection lasts for hours or days.

Coda has been designed for high availability, which is mainly reflected by its sophisticated support for client-side caching and its support for server replication.Unit of replication: volume Volume Storage Group (VSG): set of servers that have a copy of a volume Accessible Volume Storage Group (AVSG): set of servers in VSG that the client can contact Use vector versioning One entry for each server in VSG When file updated, corresponding version in AVSG is updated.Clients have access to a single shared name space.

CODA 2 PROJECT FILE UPDATE

Security Secure channels Access control on directories Client Caching Callback promise Callback break Scalability Whole file caching Smart/unreliable clients, dumb/reliable servers No system wide election Disconnected operation Optimistic update strategy and basic conflict resolution Allow files to be edited from local cache Stateful Venus Cache.

Coda 2 project file