The SDA extension commands for Extended File Cache (XFC) enable you to display the following information in a convenient and readable format: o Various XFC data structures o Statistics that aid in tuning the extended file cache You can also control the types of events that are recorded by XFC's tracing feature. You can enter XFC commands at the SDA prompt or you can access online help, as follows: SDA> XFC HELP
1 – SET
1.1 – TRACE
Controls the types of events to be recorded by XFC's trace facility and initializes the trace structures (to eliminate events that have already been recorded). Format XFC SET TRACE [/SELECT=LEVEL:level] [/RESET]
1.1.1 – Qualifiers
1.1.1.1 /SELECT
/SELECT=LEVEL:level Specifies the level of tracing in XFC on a live system. The possible values for level are as follows: 1 (Default) Traces only major, unusual events. 2 Traces file access, deacess, truncate, read start and complete, and write start and complete operations. Results are displayed using the SHOW TRACE command. Setting this trace level has only a minor performance impact. 3 Performs more detailed tracing, which can be viewed using the SHOW TRACE/RAW command. Has some performance impact. 4 Performs very detailed tracing with a noticeable performance impact.
1.1.1.2 /RESET
Initializes the trace buffer to eliminate all events that have already been traced.
2 – SHOW
2.1 – CONTEXT
Displays the contents of an XFC context block (CTX). Format XFC SHOW CONTEXT [address][/STALLING|/FULL|/BRIEF]
2.1.1 – Parameter
address The address of the CTX. If no address is supplied, then all the context structures are displayed.
2.1.2 – Qualifiers
2.1.2.1 /BRIEF
Displays a brief summary for each context; for example, the I/O type, start virtual block number (VBN), and length of I/O.
2.1.2.2 /FULL
Displays the complete context structure. This is the default.
2.1.2.3 /STALLING
Displays only contexts that are stalling; for example, those that have a stall reason code other than estrNotStalling.
2.2 – EXTENT
Displays the contents of an extent control block (ECB). Format XFC SHOW EXTENT address
2.2.1 – Parameter
address The address of the ECB.
2.3 – FILE
Displays the contents of the cache file block (CFB). Format XFC SHOW FILE [address] [/EXTENTS|/ID=file-id |/CVB=address |/OPEN|/CLOSED|/STATISTICS |/FULL |/BRIEF]
2.3.1 – Parameter
address The address of the CFB. The /OPEN and /CLOSED qualifiers, if present, are ignored. If no address is supplied, then all the CFBs are displayed.
2.3.2 – Qualifiers
2.3.2.1 /BRIEF
Displays the following summary information for each cache file block (CFB): CFB address, cache volume block (CVB) address, access count, active I/O count, and file ID. /BRIEF is incompatible with /EXTENTS, /FULL, and /STATISTICS. If the file specification is available in LIB$FID_TO_NAME(), it is displayed; otherwise, the file ID is displayed. NOTE Because the volume is accessed through its logical name, if two volumes are mounted that have the same logical name (for example, one mounted /SYSTEM and one mounted privately, which results in the same logical name in two different access-mode logical name tables), the incorrect file specification might be displayed.
2.3.2.2 /CLOSED
Displays only CFBs whose access count is zero.
2.3.2.3 /CVB
/CVB=address Displays information only for files matching the given cache volume block address.
2.3.2.4 /DISPLAY_NAME
/DISPLAY_NAME (default) /NODISPLAY_NAME Controls whether the file specification is displayed.
2.3.2.5 /EXTENTS
Displays the cache extents held in cache for any displayed files. This shows the primary and secondary cache extents along with their data state, virtual block numbers (VBNs), and logical block numbers (LBNs). It also shows a summary of memory usage (pagelets used and pagelets valid) for any displayed files. The /EXTENTS qualifier is incompatible with the /BRIEF qualifier.
2.3.2.6 /FULL
Displays all fields for each cache file block. This is the default. If the file specification is available in LIB$FID_TO_NAME(), it is displayed; otherwise, the file ID is displayed. NOTE Because the volume is accessed through its logical name, if two volumes are mounted that have the same logical name (for example, one mounted /SYSTEM and one mounted privately, which results in the same logical name in two different access-mode logical name tables), the incorrect file specification might be displayed.
2.3.2.7 /ID
/ID=file-id Displays only information about any files matching the given file-identification (FID). The file identification (FID) is the hexadecimal file number component in a format file ID (file number, sequence number, relative volume number).
2.3.2.8 /OPEN
Displays only CFBs whose access count is greater than zero.
2.3.2.9 /STATISTICS
Displays more statistics about the specified file. The /STATISTICS qualifier is incompatible with the /BRIEF qualifier.
2.4 – HISTORY
Displays approximately three days of XFC activity in 10-minute intervals. Format XFC SHOW HISTORY
2.5 – IRP
Displays a subset of the fields of an I/O Request Packet that has relevance for XFC debugging. Format XFC SHOW IRP address
2.5.1 – Parameters
address The address of the IRP structure whose relevant fields are to be decoded and displayed.
2.6 – MEMORY
Displays information about memory used by the cache. Format XFC SHOW MEMORY [/BRIEF|/FULL]
2.6.1 – Qualifiers
2.6.1.1 /BRIEF
Displays summary statistics on XFC memory use.
2.6.1.2 /FULL
Displays full statistics on XFC memory use. This is the default.
2.7 – SUMMARY
Displays general information about the Extended File Cache. Format XFC SHOW SUMMARY [/STATISTICS]
2.7.1 – Qualifier
2.7.1.1 /STATISTICS
Additionally, displays read and write activity arranged by I/O size.
2.8 – TABLES
Displays both the extent hash table (EHT) and the file hash table (FHT). Format XFC SHOW TABLES [/ALL][/EXTENT][/FILE][/SUMMARY]
2.8.1 – Qualifiers
2.8.1.1 /ALL
Displays the contents of the extent hash table (EHT) and file hash table (FHT). This is the default.
2.8.1.2 /EXTENT
Displays only the contents of the EHT.
2.8.1.3 /FILE
Displays only the contents of the FHT.
2.8.1.4 /SUMMARY
Displays summary information about EHT and FHT.
2.9 – TRACE
Displays all or selected portions of the XFC trace buffer, starting with the most recent entry and moving backward in time. Format XFC SHOW TRACE [/ALL]/CONTAINING=value |/CPU=cpu-num |/LINENUMBER=linenumber |/MATCH [=[AND|OR]] |/Px=value |/RAW]
2.9.1 – Qualifiers
2.9.1.1 /ALL
Displays the entire trace buffer. This is the default.
2.9.1.2 /CONTAINING
/CONTAINING=value Displays only records where any of the traced parameters is equal to value.
2.9.1.3 /CPU
/CPU=cpu-num Displays only records from threads executing on CPU cpu-num.
2.9.1.4 /LINENUMBER
/LINENUMBER=linenumber Displays only records from tracepoints at line linenumber in the relevant source files.
2.9.1.5 /MATCH
/MATCH [= AND|OR] Alters the sense of the match condition when more than one of the filter qualifiers /CPU, /LINENUMBER, /FILENAME, /Px, or /CONTAINING are specified.
2.9.1.6 /Px
/Px=value Displays only records where one of the traced parameters P1, P2, P3, or P4 is equal to value.
2.9.1.7 /RAW
Displays contents of trace records in hexadecimal format without interpretation. By default, the values are displayed in human readable format with filenames.
2.10 – VOLUME
Displays the contents of a cache volume block (CVB). Format XFC SHOW VOLUME [address]/BRIEF|/FULL| /NAME=DISK$volume_label| /STATISTICS
2.10.1 – Parameter
address The address of a CVB. If no address is supplied, then all volumes are displayed.
2.10.2 – Qualifiers
2.10.2.1 /BRIEF
Displays summary information for each volume.
2.10.2.2 /FULL
Displays a complete list of information about each volume. This is the default.
2.10.2.3 /NAME
/NAME=DISK$volume_label Displays information for the volume with the specified name.
2.10.2.4 /STATISTICS
Displays the read and write I/O activity for this volume. The /STATISTICS qualifier is incompatible with the /BRIEF qualifier.