HPUX SAR %busy value more than 100%

[Chin Kim Keong]

Hi

I have encounter a value of over 100% (eg 100.25%) in HP Sitescope report which is using hpux.sar command.

Thus I would to know is there any additonal meaning to it if I/O %busy is over 100%?

Thanks.

[Johnson Punniyalingam]

It would be also better to double check with

iostat -> commands if I/O 100% could be disk bottle neck ,



$ iostat -xtc 5 2
extended disk statistics tty cpu
disk r/s w/s Kr/s Kw/s wait actv svc_t %w %b tin tout us sy wt id
sd0 2.6 3.0 20.7 22.7 0.1 0.2 59.2 6 19 0 84 3 85 11 0
sd1 4.2 1.0 33.5 8.0 0.0 0.2 47.2 2 23
sd2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0
sd3 10.2 1.6 51.4 12.8 0.1 0.3 31.2 3 31


The fields have the following meanings:

disk name of the disk
r/s reads per second
w/s writes per second
Kr/s kilobytes read per second
Kw/s kilobytes written per second
wait average number of transactions waiting for service (Q length)
actv average number of transactions actively
being serviced (removed from the
queue but not yet
completed)
%w percent of time there are transactions waiting
for service (queue non-empty)
%b percent of time the disk is busy (transactions
in progress)

[Johnson Punniyalingam]

The values to look from the iostat output are:

Reads/writes per second (r/s , w/s)
Percentage busy (%b)
Service time (svc_t)
If a disk shows consistently high reads/writes along with , the percentage busy (%b) of the disks is greater than 5 percent, and the average service time (svc_t) is greater than 30 milliseconds

Your disks are located external or Internal ?

if its 100% busy it could disk bottle neck

* disk going to fail
* check your storage disk & Internal disks
* check fc, scsi path from storage
* dd -> command to check Health of disk

identify disk which busy "and confirm disk health by dd -> command

this command will check whether the disk is realy bad
***********************************************
# dd if=/dev/dsk/cxtxdx of=/dev/null bs=128k

[Chin Kim Keong]

firstly thanks for the reply.

I am sorry I was trying to find out any interpretation if the %busy's value is 100.25%, what does the additional 0.25% means in a SAR returned results?

[Johnson Punniyalingam]

>>what does the additional 0.25% means in a SAR returned results?<<<

It means your disk being utilised above 100%

[Johnson Punniyalingam]

https://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1369041

Check above thread

[Duncan Edmonstone]

I suspect this is just a rounding error or some other form of arithmetic error... you can't have a disk more than 100% busy...

disk utilisation percentages are pretty meaningless anyway - is there a reason you care?

HTH

Duncan

[Amitav]

Execute dd command to check the integrity of the disk...!!