CLAYTON@XRT.UPENN.EDU ("Clayton, Paul D.") (07/01/88)
Celeste Finison has asked the following question. > For those of you on the net familiar with VMS 5.0 and the configuration rules > for the mixed-interconnect cluster: > > Will it be possible for me to MSCP serve an HSC disk via a CI cluster node(s) > so that it may be mounted by a MicroVAX on the same ethernet that has booted > from its own locally attached system disk? If not why not? There are several items to note here. 1. There is NO mention of the KEY word/phrase 'LAVC' in the question. If the question deals with two processors that are connected by Enet, BUT NOT part of the SAME cluster then you will NOT be able to share the disks. This is due to having the controller of who gets what, the 'connection manager' and 'lock manager' work ONLY in a 'CLUSTER' configuration. The only way to share disks in a non-cluster configuration is to use the DECnet access methods, MSCP is not available. 2. A HSC disk, by definition, will essentially be MSCP served in a mixed CI/NI configuration. A disk that is attached to a HSC will have a CI processor serve as the 'gateway' to it for its NI brothers/sisters. HSC based disk failover is supported by the processors with the CI interface. The NI processors will not be involved in the failover process, except to requeue outstanding I/O requests. 3. A local NI based UDA/KDA/KDB disks CAN be, but does not HAVE to be, available to the other cluster nodes. It is determined by doing a '$SET DEVICE/SERVED' and loading the MSCP driver. The latest word that I have heard indicated that UDA/KDA/KDB based disk failover will not be available until the 5.2 time frame. The assumption here, being that the disk(s) MUST have the same 'allocation class' (SYSGEN parameter ALLOCLASS) and channel assigments (for example DUAxx) on BOTH sides of the 'A' and 'B' channels. Hope this helps. :-) pdc Paul D. Clayton Address - CLAYTON%XRT@CIS.UPENN.EDU Disclaimer: All thoughts and statements here are my own and NOT those of my employer, and are also not based on, or contain, restricted information.