Summary statistics for each object
are printed in single line output records,
preceded by two header lines.
The output line consists of
blank-separated fields for the file name,
and statistics on read and write operations:
|
o
|
number of read operations
|
o
|
number of write operations
|
o
|
number of blocks read
|
o
|
number of blocks written
|
o
|
average time spent on read operations in the interval
|
o
|
average time spent on write operations in the interval
|
If the
-i interval
option is supplied,
statistics are prefaced with a time stamp
showing the current local time on the system.
If the
-l option is specified,
statistics are printed in two lines per object:
|
|
FILE NAME NREADS NWRITES RBLOCKS WBLOCKS RTIME WTIME
NREQUESTIO NDISKIO HIT RATIO
cust0 2 1 8 4 5.0 10.0
2 1 50.0
|
|
The first line is the same as described above.
The second line shows the caching statistics.
Cached Quick I/O performs buffered reads and returns
cached data (if available) without
doing reads from the disk.
Writes are performed as modified direct writes,
that is,
after the direct write to disk is scheduled,
the file system updates the copy of data in cache
(if it exists)
with the same data being written to disk.
In the column headings of the second line:
|
o
|
NREQUESTIO
is the total number of reads issued by the user.
|
o
|
NDISKIO
is the total number of reads of the disk required because the data
was not available in cache, plus the read ahead I/O if you enabled
the read ahead option on the file system.
|
o
|
HIT RATIO
is the percentage of the read requests that
did not have to perform physical
I/O and were satisfied from the cache.
HIT RATIO
is calculated as follows:
|
|
(NREQUESTIO - NRANGEIO) * 100 / NREQUESTIO = HIT RATIO
|
|
NRANGEIO
is the number of reads requested by the user of the disk required
because the data was not available in cache.
|