From claimed to no_hw

[Danny Baldono]

I got two unix (11i) machines and a four-tape drive library connected thru san. At the beginning all the drives can be seen (claimed) by the two servers but eventually the drives on one controller cannot (no_hw) be seen. The library has two controllers with two tape drives on each controller.

I've read a thread to set the value of st_san_safe to 1. I've changed the value from 0 to 1, after the reboot all the drives can be seen (claimed) but cannot tar (cannot open device) and even diskinfo (invalid argument).
It is look like I can see the drives (claimed) but I cannot access those drives.

[Torsten. · Accepted solution]

Is this a MSL lib?

Did you reboot the server or the lib?
You have to powercycle the lib to reset the storage routers.

In case you rebooted the lib, there may some backup processes hung. Use lsof or fuser to find and kill them.

I would install HPs LTT and check the firmware of the storage routers.

http://www.hp.com/support/tapetools

[Miguel Hernández]

Try insf -e

test and you tell me again.

[Danny Baldono]

Hi Torsten,

Yes, I made a new kernel and rebooted the unix machine also verified thru sam that the value was change to 1. I did not power cycle/reboot the library but one thing I observed is that even the local DDS3 drive
(used in archiving) also cannot be accessed. It is look like that when you set the st_san_safe to 1 all the drives cannot be accessed. Is it really required to change the value of st_san_safe to one.
What st_san_safe really do?

Hi Miguel,

With st_san_safe equal to 0, all the drives can be seen but eventually it will be no_hw.
I think you cannot do insf on no_hw?

Danny

[Torsten.]

Read first, than modify!

http://docs.hp.com/en/B2355-60105/st_san_safe.5.html

[Miguel Hernández]

It seems to me to have read that you see claimed all devices with st_san_safe to 1.

which device file are you using with tar???

[Danny Baldono]

Hi Torsten,

The document was very helpful. I tried to enable the st_san_safe to 1. I observed that the only tape device files I can use
are those that has "n" (no rewind) at the end. When in terms of reading and writing, what is the difference between 0m (rewind)and 0mn (no rewind).

Danny

[Matti_Kurkela]

The only difference between the 0m (auto-rewind) and the 0mn (no-auto-rewind) tape devices is that when you use the 0m device, the OS automatically sends a "rewind to start of tape" after the application closes the device, even if the device is opened just for a tape drive status query.

The 0mn device does not do that. If an application using a 0mn device requires the tape to be rewound to the start position, it must explicitly send the rewind command.