HFS Statistics Report
The HFS Statistics Report provides information about caching by HFS buffer pools and mounted file systems.
The HFS Statistics Report is produced by using the HFS Analyzer control statement. The data for this report is obtained by using the HFS Extractor control statement.
This report consists of three sections:
- Global Statistics
This section displays storage that is used by all buffer pools and overall caching of metadata and the first page of files. - Buffer Pool Statistics
This section displays storage that is used and I/O activity between buffers and DASDs for each buffer pool. File System StatisticsThis section displays storage that is used, I/O requests of files, caching of metadata, index, and the first page of files for each mounted file system.
The report might issue the error message ERROR: bad-data UNAVAILABLE RC=cccccccc-rrrrrrrr, where bad-data is BUFFER LIMITS, BUFFER STATS, or STATISTICS. The return code cccccccc and the last four digits of reason code rrrrrrrr are documented in the z/OS UNIX System Services Messages and Codes manual.
An example of the HFS Statistics Report is shown in the following figure.
BMC SOFTWARE, INC. BMC SOFTWARE, INC. REPORT DATE: DD MMM YY11.35
REQD 27 JUL 06 09.45.00 27 JUL 06 23.59.59 HOUSTON, TX. SYSTEM ID: SJSD Z v.rr.n
ACTL 27 JUL 06 09.45.00 27 JUL 06 11.15.00 REPORT CYCLE: CYCLE099
BASED ON REC TYPE/# RECS/# SAMPLES/REC HOURS: 74-6/6/0/1.5
-------------------------------------------------------- GLOBAL STATISTICS ---------------------------------------------------------
---------- STORAGE (MB) ----------- ------------------------ I/O ACTIVITY -------------------------
-- LIMITS -- -- IN USE -- ----- FILE 1ST PAGE ------ -------- METADATA --------
RATE COUNT HIT RATIO RATE COUNT HIT RATIO
TOTAL MAX 2,011 6.250 CACHE 0 1 100 1.068 5,768 99.8
FIXED MIN 0 0 DASD 0 0 0.002 10
------------------------------------------------------ BUFFER POOL STATISTICS ------------------------------------------------------
-------------- STORAGE -------------- ------------- I/O ACTIVITY --------------
BUFFER DATA BUFFERS PAGES BYTES % FIXED --- TOTAL ---- --- FIXED ---- % FIXED
SIZE SPACES RATE COUNT RATE COUNT
1 1 784 784 3,136K 0 0.291 1,571 0 0 0
4 1 4 16 64K 0 0 0 0 0 0
16 1 14 224 896K 0 0 0 0 0 0
64 1 9 576 2,304K 0 0 0 0 0 0
------------------------------------------------------ FILE SYSTEM STATISTICS ------------------------------------------------------
FILE SYSTEM - BBO.V60.SJSE.BASE.CONFHFS MOUNTED: 07/27/2006 04:27:29 DURATION: 01.30.00
STORAGE - ALLOCATED: 176M USED: 137M ATTR DIR: 11,740K CACHED: 3,616K
------- DATA I/O -------- -1ST PAGE I/O- -METADATA I/O- -- INDEX I/O - -- INDEX EVENTS --
RATE COUNT RATE COUNT RATE COUNT RATE COUNT COUNT
SEQUENTIAL 0 0 CACHE 0 0 2.086 11,265 2.137 11,543 NEW LEVELS 0
RANDOM 0 0 DASD 0 0 0 1 0 1 SPLITS 0
HIT RATIO 0 100 100 JOINS 0
FILE SYSTEM - USS.BBPLEX01.ROOT MOUNTED: 07/27/2006 00:14:09 DURATION: 01.30.00
STORAGE - ALLOCATED: 5,040K USED: 4,916K ATTR DIR: 52K CACHED: 0K
------- DATA I/O -------- -1ST PAGE I/O- -METADATA I/O- -- INDEX I/O - -- INDEX EVENTS --
RATE COUNT RATE COUNT RATE COUNT RATE COUNT COUNT
SEQUENTIAL 0 0 CACHE 0 0 2.697 14,566 2.702 14,593 NEW LEVELS 0
RANDOM 0 0 DASD 0 0 0.002 9 0 0 SPLITS 0
HIT RATIO 0 99.9 100 JOINS 0
FILE SYSTEM - USS.SJSE.VAR MOUNTED: 07/27/2006 00:14:10 DURATION: 01.30.00
STORAGE - ALLOCATED: 6,528K USED: 1,924K ATTR DIR: 80K CACHED: 0
------- DATA I/O -------- -1ST PAGE I/O- -METADATA I/O- -- INDEX I/O - -- INDEX EVENTS --
RATE COUNT RATE COUNT RATE COUNT RATE COUNT COUNT
SEQUENTIAL 0 0 CACHE 0 0 1.977 10,676 1.977 10,676 NEW LEVELS 0
RANDOM 0 0 DASD 0 0 0 0 0 0 SPLITS 0
HIT RATIO 0 100 100 JOINS 0
HFS Statistics Report field descriptions
The table below describes each field in the Global Statistics section of the HFS Statistics Report.
Field | Description | |
|---|---|---|
STORAGE (MB) | virtual storage (in megabytes) of HFS buffers at the end of the duration of the report | |
TOTAL | LIMITS - MAX | maximum amount of virtual storage that HFS buffers should use; this value is specified by the VIRTUAL(max) parameter in BPXPRM xx member or the USS CONFIGHFS command |
IN USE | total amount of virtual storage in use by all HFS buffer pools | |
FIXED | LIMITS - MIN | minimum amount of fixed storage for HFS buffers; this value is specified by the FIXED(min) parameter in BPXPRM xx member or the USS CONFIGHFS command |
IN USE | total amount of fixed storage in use by all HFS buffer pools | |
I/O ACTIVITY | I/O activity of metadata and the first page of files | |
FILE 1ST PAGE | CACHE - RATE | average number of times per second that the first page of a data file was requested and found in virtual storage (cache) |
CACHE - COUNT | number of times that the first page of a data file was requested and found in cache | |
HIT RATIO | percentage of times that the first page of a data file was requested and found in cache | |
DASD - RATE | average number of times per second that the first page of a data file was requested and not found in cache, and an I/O was necessary | |
DASD - COUNT | number of times that the first page of a data file was requested and not found in cache, and an I/O was necessary | |
METADATA | CACHE - RATE | average number of times per second that metadata was found in cache during file lookup |
CACHE - COUNT | number of times that metadata was found in cache during file lookup | |
HIT RATIO | percentage of times that metadata was found in cache during file lookup | |
DASD - RATE | average number of times per second that metadata was not found in cache during file lookup, and an index call was necessary that can result in I/O | |
DASD - COUNT | number of times that metadata was not found in cache during file lookup, and an index call was necessary that can result in I/O | |
The following table describes each field in the Buffer Pool Statistics section of the HFS Statistics Report.
Field | Description | |
|---|---|---|
BUFFER SIZE | size (in pages) of each buffer in the buffer pool | |
DATA SPACES | number of data spaces allocated for the buffer pool | |
STORAGE | BUFFERS PAGES BYTES | total amount of virtual storage in use by the HFS buffer pool in units of buffer, page, and byte |
% FIXED | percentage of buffer pool in permanently fixed storage | |
I/O ACTIVITY | I/O activity between buffer pools and DASDs | |
TOTAL | rate per second and count of all I/O requests | |
FIXED | rate per second and count of I/O requests where a buffer was already fixed prior to I/O | |
% FIXED | percentage of I/O requests where a buffer was already fixed prior to I/O | |
The following table describes each field in the File System Statistics section of the HFS Statistics Report.
Field | Description | |
|---|---|---|
FILE SYSTEM | name of the MVS HFS data set containing the file system | |
MOUNTED | date and time (mm/dd/yyyy hh:mm:ss) when the file system was last mounted If mount time changed (that is, the file system was remounted), an asterisk is displayed after the time. If the file system was never mounted, three dashes are printed. | |
DURATION | sum of recording intervals (ddd.hh.mm.ss) during which statistics for the file system were collected; this is the divisor in the calculation of all Rate columns | |
STORAGE | ALLOCATED | amount of storage on DASDs allocated to the file system |
USED | amount of storage on DASDs actually used by the file system | |
ATTR DIR | amount of storage on DASDs used by the file system for attribute directory | |
CACHED | amount of storage in HFS buffer pools cached for this file system | |
DATA I/O | rate per second and count of sequential and random I/O requests of files | |
1ST PAGE I/O | CACHE | rate per second and count of requests for the first page of a file where it was found in cache |
DASD | rate per second and count of requests for the first page of a file where it was not found in cache and I/O was necessary | |
HIT RATIO | percentage of requests for the first page of a file where it was found in cache | |
METADATA I/O | CACHE | rate per second and count of requests for metadata where it was found in cache during file lookup |
DASD | rate per second and count of requests for metadata where it was not found in cache during file lookup | |
HIT RATIO | percentage of requests for metadata where it was found in cache during file lookup | |
INDEX I/O | CACHE | rate per second and count of requests for index page where it was found in cache |
DASD | rate per second and count of requests for index page where it was not found in cache | |
HIT RATIO | percentage of requests for index page where it was found in cache | |
INDEX EVENTS | NEW LEVELS | rate per second and count of requests for index page where it was found in cache |
SPLITS | rate per second and count of requests for index page where it was not found in cache | |
JOINS | percentage of requests for index page where it was found in cache | |
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