I am experiencing a two minute timeout open()ing a tape device when

there is no tape in the drive.
open() with O_NONBLOCK succeeds immediately, however.
The problem is that I am trying to set up Legato on a system that has

multiple tape drives. For certain common operations, Legato tries to

open() each tape drive multiple times. On a system with multiple tape

drives, this adds up to a significant amount of time wasted due to

this timeout.
Solaris does not have this problem, and Legato support advises that

they are at the mercy of the operating system.
Changing the timeout with e.g. "mt -f /dev/nst0 sttimeout 15" does not

change the timeout to 15 seconds, it is still exactly 2 minutes.
This happens with kernel 2.6.24.4, as well as RedHat's 2.6.9-67.
Here is a snippet of strace -T -tt output:
15:56:18.688392 open("/dev/nst0", O_RDONLY) = -1 ENOMEDIUM (No medium

found) <120.480482>
In this case, the tape device is a Quantum DLT-S4 connected to with an

Emulex FC card, via a Fibre Channel SAN.
Any help would be appreciated. Thanks.

--

This is how open() is supposed to work according to standards (e.g., SUS)

if O_NONBLOCK is supported. (Well, actually open() should wait

indefinitely but the non-linux systems I tested had a timeout.) The linux

st driver was changed to comply with standards at 2.5.3. I.e., the 2.4

You are not the only person who has noticed this. At work we had to

install a distribution using 2.4 kernel to our backup server in order to

use Legato ;-(
Solaris does return EIO. Either it does not support O_NONBLOCK or it is

not compliant with SUS.
Legato would not be so much "at the mercy of the operating system" if they

would write their software to work according to standards, not according

to some operating system.
--

Kai

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