The dfstrace command suite allows a system administrator to manipulate the two main elements of the underlying DFS trace facility: the event set and the trace log.
An event set is a logical grouping of related kernel or server process events. Events with similar characteristics are grouped into event sets to aid in the diagnosis of specific types of problems. When an event in an event set occurs, a message is logged to each appropriate trace log; event set information from one event set can be written to from one to eight trace logs.
An event set can be in one of three states:
· active - Tracing is enabled for the event set.
· inactive - Tracing is temporarily disabled for the event set; however, the event set continues to claim space occupied by the logs to which it sends data.
· dormant - Tracing is disabled for the event set; furthermore, the event set releases its claim to space occupied by the logs to which it sends data. When all of the event sets that send data to a particular log are in this state, the space for that log is deallocated.
Following are some of the DFS kernel event sets that you can trace:
· cm - Cache Manager package
· fshost - File exporter host package
· fx - File exporter package
· episode/anode - LFS anode package
· episode/logbuf - LFS buffer/logging package
· episode/vnops - LFS vnode package
· tkc - Token cache package
· tkm - Token manager package
· tpq - Thread pool queue package
· xops - Vnode-to-fileset synchronization package
Following are some of the server process event sets that you can trace:
· bosserver - bosserver package
· dacl - DFS ACL package
· dfsauth - DFS security package
· flserver - flserver package
· ftserver - ftserver package
· ftutil - Fileset utility package
· ubikdisk - Disk I/O subset of Ubik package
· ubikvote - Sync site election subset of Ubik package
A trace log is a piece of memory within the kernel or server process where event information is written when an event associated with an active event set occurs. Multiple event sets that contain related events often write information to the same log to aid in problem diagnosis. Every trace log has a default size assigned to it; however, the size of a log can be increased or decreased.
A trace log can either be allocated or deallocated:
· When a trace log is allocated, space is allocated for it in the kernel or server process memory. A trace log is allocated when one or more of the event sets that write to the log are either active or inactive.
· When a trace log is deallocated, no space is allocated for the log in the kernel or server process memory. A trace log is deallocated when all of the event sets that write to the log are dormant.
Both event sets and trace logs can have a persistence attribute permanently assigned to them. If an event set is persistent, its state cannot be set as part of a global event set state setting (performed with the dfstrace setset command), but its state can be manipulated if indicated explicitly. If a trace log is persistent, it cannot be cleared as part of a global log clearing (performed with the dfstrace clear command), but it can be cleared if indicated explicitly.
More:
General Recommendations for Diagnosing DFS Problems