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I am on Solaris 11 and I am seeing the following %w=32 %b=62

                extended device statistics
    r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device
   47.5 2564.6 1460.1 33481.8 62.1 93.0   23.8   35.6  **32  62** c0t60060E801054EB40056FD74400000015d0

From the doc

%w percent of time there are transactions waiting for service (queue non-empty)

%b percent of time the disk is busy (transactions in progress)

What does it means to have a device not being busy at 100% (%b=62) but still have 32% waiting queue.

I always thought there would be queue only if the device is 100% busy

I know I am wrong, but can someone shed some light on this

Thanks

HBruijn
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Noob
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1 Answers1

2

I always thought there would be queue only if the device is 100% busy

The disk isn't always 100% busy. Sometimes it hits 100%, sometimes it hits 0%.

Per Solaris 11 iostat documentation:

r/s

    Reads per second
w/s

    Writes per second
kr/s

    Kbytes read per second
kw/s

    Kbytes written per second
wait

    Average number of transactions that are waiting for service (queue length)
actv

    Average number of transactions that are actively being serviced
svc_t

    Average service time, in milliseconds
%w

    Percentage of time that the queue is not empty
%b

    Percentage of time that the disk is busy

So 

           extended device statistics
r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device
47.5 2564.6 1460.1 33481.8 62.1 93.0   23.8   35.6  32  62 c0t60060E801054EB40056FD74400000015d0

merely means the queue for this device had something in it 32% of the time.

How long is your sample time?

If this is the first line of output, it represents the disk statistics since the server was last rebooted.

Andrew Henle
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