HI all ,
I am checking the total throughput obtained from local SCSI disk when performing the I/O on it using ?dd? command.
My system configuration is as below
Hardware -> Intel(R) Xeon(TM) CPU 2.80GHz
OS -> Linux 2.6.9-5.18AXsmp
SCSI controller & disk -> AIC7902 Ultra320 SCSI adapter SEAGATE Model: ST336607LC
sdb disk is of size 34 GB.
I am checking the throughput using ?iostat? utility.
But for write case with low input/output block sizes (512B , 1KB )
Using
# dd if=/dev/zero of=/dev/sdb bs=BLOCK
Where BLOCK = 512, 1024
I am getting both readbyte/sec and writebyte/sec in output of iostat(though it is write case readbyte/sec should be 0)
obtained using
# iostat ?d sdb 5 100
for all data block sizes(e.g. 2K , 4K , 8K 16K) the results are normal.
When I partitioned the sdb disk as sdb1 and sdb2
and run the above test on partition sdb1 the results obtained from iostat are normal (readbyte/sec are 0)
but when run on partition sdb2 the results for low block size(512 byte,1 KByte ,2 KByte) are abnormal, getting both readbyte/sec and writebyte/sec output from iostat. and for all other write case (e.g 4k 8K ....) output of iostat is normal
If anyone could please clarify the cause of this abnormal behaviour.
Thanks in advance.
Regards,
Satinder
Yahoo! India Matrimony: Find your partner online.
Go to http://yahoo.shaadi.com
