DISKWRITER

Purpose:
Informix must rely on the OS to write all data it receives from the storage manager to the associated disks. The purpose of this utility is to measure how fast the OS can actually write data to a given chunk.

How To Use:
To use this uility you must first compile the C code to an executable.

USAGE
usage: diskwriter <-f filename> [options...]
options are:
        -b blocksize   (default 16384)
        -n numblocks   (default 1048576)
        -s random seed (default 122864)
        -r value       (default 1 (1-256 allowable))
        -v interval    (default OFF)
-f is the chunk pathname
-b blocksize (in Bytes). Should be set to 4*PAGESIZE
-n number of blocks.
-v will display timings. Suggested setting: 0

Sample command with output
server> ./diskwriter -f /data6/table1/data3 -b 16384 -n 6250 -v 0

Transfer rate for 100000.00 kbytes in 67.0 seconds is 1492.54 kbytes/sec
server>
server>

Please Note:
If you are using cooked files then it can be very difficult to accurately measure the throughput. The cooked file its self can be cached in memory at some points and not cashed in others.


MAJOR WARNING
This utility DOES overwrite the specified chunk (passed in by filename). Make sure you either dont care that it gets overwritten or have a backup/archive of that data/chunk. This is the only way to accurately measure write throughput.

Download:
diskwriter.tar
Not available yet! Please Email tiller@informix.com for an advanced copy.




Compiling the Source:
You must compile the source code to an executable. On Solaris platforms the complie line will look like the following:
make diskwriter
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