ioscan -fu and no_hw returned for that device

[JOHN S GASPER]

A customer of mine uses the ioscan -fu to check the "health" of his systems. This ioscan
is within a remote shell that runs as a batch
every four minutes. A status of no hardware found ( no_hw ) is returned ocassionally
on disk or tape devices. Usually a second ioscan shows claimed. If four scans return
no hardware found then a alert is then ftp'd
to a paging application. Usually a ioscan after this shows claimed. WHY is this??

[Kevin Wright]

sounds like an intermitten HW problem to me, is the device scsi or fiber, replace the channel/cards is where I would start. how about when you do a ioscan -fnC tape??

[JOHN S GASPER]

I dont beleive this is a hardware problem persay. This sympton appears on more than one platform. There are approximately 33 systems.
I have seen NO_HW on the internal dds2's on k
systems or even dlt's on L,N class systems. No_HW also appears on disc fiber channel or even scsi channels. Usually a second ioscan
shows that the hardware is claimed!
Just trying to find out why??

[Karthik_2]

John,
Not sure running ioscan every 4 minutes is a good idea .On a system will a lot of i/o devices this will eat up all system resource.
NO_HW means that the hardware is not responding to the query it may be either inaccesable temporarily of quiet busy.
Would recommend increasing the interval between a min of atleast 15 mins.
Let me know if this helps.

Cheers
Karthik...

[Karthik_2]

John,
Another thought ..make sure u have the latest SCSI cumulative patches installed as well I remember once there was a patch released for a similar issue eith the SCSI INQUIRY command.

Karthik...

[Vincenzo Restuccia]

Verify with STM diagnostic this device.