nodeapps demons

ONS-it is responsible for events,connecttions failure
GSD-monitor GUI applivations
VIP-keeps the vip status of vip-address of the node

cluster demons

demon means background process
crsd - it is update the ocr file. it use for node apps work(ons,vip,gsd)
cssd - it is update the vd file. it is monitor the node membership
when ever HB(heart beat) fail between the nodes the cssd process reboot the node
evmd - update the diag information

GRD(global resource directory)

it is part of the shared pool
whenever a block is transfered out of local cache to another instance's cache grd is updated
it holds the meta data about data blocks, that are availble in DBBC
it holds information like
1.SCN(system change number)
2.DBI(datablock identifier)
3.location of the block
4.mode of the block
1.null (N) - indicates the their are noacess rides on block
2.shared(S) - indicate block is share across the all instance
3.exclusive(E) - access rides only for particular instance
5.role of the block
1.local-date block image present in only one node
2.global-data block image present in multiple nodes
6.types of datablock image
1.current image-update data block value
2.consistent image-previous data block value
2.past image-grd updated image
it convert to current image when instance is crash



grd is depend on ges,gcs services