I tried the command on the RS/6000 connedted with 7135-110.
$ iostat
TTY: TIN TOUT CPU: % USER % SYS % IDLE % IOWAIT
0.7 22.6 17.8 51.8 30.3 0.2
DISKS: % TM_ACT KBPS TPS KB_READ KB_WRTN
HDISK0 0.3 1.4 0.3 117405 232938
HDISK1 0.1 0.2 0.0 2816 48588
CD0 0.0 0.0 0.0 7882 0
DAC0 0.0 0.0 0.0 0 0
HDISK2 0.1 1.2 0.2 118641 173640
NOTE:
HDISK2 is connected with DAC0 ( Disk Array Controller ).
HDISK0 and HDISK1 are connected with SCSI adapter.
I heard that iostat report i/o statics for tty, disk, and cdrom.
But this output includes the Disk Array Controller, and it's value
are all zero.
So, my questions as follows.
(1) Is the Disk Array Controller considered as Disk?
(2) If (1) is true, Does iostat have any function for accounting DAC0,
doesn't it?
ANSWER
The performance commands in AIX were not designed to work with
RAID devices. Since these are composed of multiple disks the
information returned for a LUN is not reliable. The DAC is
not considered a hdisk, and iostat does not have a way of
getting performance numbers from the DAC. Also, as before the
numbers returned for a LUN are not necessarily accurate.
S e a r c h - k e y w o r d s:
IOSTAT AND 7135
WWQA: ITEM: RTA000079099 ITEM: RTA000079099
Dated: 02/1995 Category: ITSAI6000CO
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