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.