Known ioscan issue?

[hpuxrox]

Hello,

I have been told of a known issue with running ioscans on a box that is direct connected to a TAN.
I was told that it could cause backups to fail or hang and never to run it. This makes thing really hard as an administrator to do any task without ioscan. It???s like having surgery on your stomach and finding out how much you really do use your stomach muscles.

I haven???t seen any documentation on this issue and would really like to get to the root of it. So maybe someday I can use my ioscans again. Can someone lead me in the right direction?

[Bill McNAMARA_1 · Accepted solution]

ioscan can potentially hang busses/drivers when it scans.

If you have added no hardware/devices to your system since the last ioinit (on bootup) use an ioscan with the -k option which is perfectly safe.

ie:
ioscan -fnk

Notice the time difference between o/p of
ioscan -fn
and
ioscan -fnk

DO NOT have 2 ioscans (without -k) running simultaneously, ps -ef | grep ioscan before running one.

Certain disk array monitors will run them on startup.

Later,
Bill

[hari jayaram_1]

Hi Yates,

I assume you mean SAN and not TAN. I have not had any issues in running ioscans on direct connect sans till date and they have definetly not affected my backup( Netbackup) all are using EMC symmetrix. Is there any specific problem ?
If it is TAN could you please expand.

Thanks

Regards

Hari

[hpuxrox]

No it is a TAN. All I know is, Ive never had an issue with it before. Im on a new project and that is what they are telling me here. I am just trying to find what the heck they are talking about.

[Jeff Schussele]

Hi,

I think Bill's response is on the right track
And for us dummies - please define TAN.
Is it Tape Area Network?

Thx,
Jeff

[Bill Hassell]

Unfortunately, the default options for ioscan will search all I/O cards and possible devices, and depending on how strange the I/O structure is, or if a broken device does not timeout properly, ioscan could hang some drivers.

There is no need to run ioscan without -k unless you are trying to discover new devices that were connected while the system was still running (which is always dangerous). The -k option tells ioscan to obtain it's information from kernel memory (which won't hang). And one other advantage: ioscan -k is about 20 to 100 times faster.