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тАО10-15-2008 01:47 PM
тАО10-15-2008 01:47 PM
Can read raw disk but not block device
This is from the problem system:
root@(hcidb1) [/etc/Navisphere]
# dd if=/dev/rdsk/c5t0d3 of=/dev/null bs=1024
3001+0 records in
3001+0 records out
root@(hcidb1) [/etc/Navisphere]
# dd if=/dev/dsk/c5t0d3 of=/dev/null bs=1024
dd read error: I/O error
0+0 records in
0+0 records out
root@(hcidb1) [/etc/Navisphere]
And this is from the "good" system:
root@(hcidb2) [/root]
# dd if=/dev/rdsk/c5t0d3 of=/dev/null bs=1024
3813+0 records in
3813+0 records out
root@(hcidb2) [/root]
# dd if=/dev/dsk/c5t0d3 of=/dev/null bs=1024
37720+0 records in
37720+0 records out
root@(hcidb2) [/root]
#
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тАО10-15-2008 01:51 PM
тАО10-15-2008 01:51 PM
Re: Can read raw disk but not block device
BTW, HPUX 11.31 includes multipathing natively. You can some some $$ by removing powerpath someday when you wish. ( maybe you already know this).
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тАО10-16-2008 09:48 AM
тАО10-16-2008 09:48 AM
Re: Can read raw disk but not block device
As i believe You cannot read a block device if the same device is presented on multiple devices, but you can read a raw device.
Manoj K
Manoj K
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тАО10-16-2008 10:00 AM
тАО10-16-2008 10:00 AM
Re: Can read raw disk but not block device
On some systems, having both a mounted file system and a block special
file open on the same device can cause unpredictable results; this
should be avoided if possible. This is because it may be possible for
some files to have private buffers in some systems.
So is that disk actually in use?
I'm not familiar with PowerPath on a 11.31 system (can't imagine why you'd want it for starters), so am not sure how it works in relation to legacy and agile DSFs. If you use "ioscan -m dsf" to identify the agile DSF for c5t0d3 and then try the dd on the agile DSF block device does that work?
HTH
Duncan
I am an HPE Employee
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тАО10-16-2008 10:20 AM
тАО10-16-2008 10:20 AM
Re: Can read raw disk but not block device
That being the case, I reinstalled Powerpath and the problem went away.
I did find the following the following in the Powerpath installation documentation:
"PowerPath 5.1 disables at the device level native multipathing for
legacy-style devices. When devices are configured for PowerPath
(for example, when you run powermt config), PowerPath
disables native multipathing on the devices it manages by setting
to false the leg_mpath_enable attribute."
My hunch is that this was the problem, but we had to get on with installing the application, so I lost my test bed.
We do have another server I might be able to experiment with, but that won't be for a while. So, I'm leaving this thread open since it seems to be pretty arcane, and I might have an update, but I don't need any help right now.
Thanks to those who responded.
Tim: Thanks for replying to my other thread. I found a "solution" and gave you some points.
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тАО08-04-2010 04:17 PM
тАО08-04-2010 04:17 PM
Re: Can read raw disk but not block device
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тАО08-04-2010 04:17 PM
тАО08-04-2010 04:17 PM