partx fails 4096 block size

partx fails 4096 block size

[Ross Anderson]

Greetings,

I posted a similar error a while back. This is using multipath tools 
from GIT as of today. kernel version 3.10.49.

Devices are 4k GPT partition created under windows.

They are running SFS file system (cluster multi os)

udev detects individual paths and they are fully functional.

Multipath creates primary dm-0 devices and alias links however no 
partition point is created. Error output is very limited.

I'd appreciate any help in troubleshooting this. Quiet frustrating not 
being able to use mpath on 4k blocks.

http://pastebin.com/EbTMXdvE

Thanks,
Ross

Re: partx fails 4096 block size

[Bryn M. Reeves]

On Mon, Sep 15, 2014 at 02:48:23PM -0500, Ross Anderson wrote:
> I'd appreciate any help in troubleshooting this. Quiet frustrating not being
> able to use mpath on 4k blocks.

Doesn't seem related to sector size.
 
> http://pastebin.com/EbTMXdvE

> ###partx -a-v
> partition: none, disk: /dev/dm-0, lower: 0, upper: 0
> /dev/dm-0: partition table type 'gpt' detected
> partx: /dev/dm-0: adding partition #1 failed: Invalid argument

partx is trying to call a BLKPG partition management ioctl on a
device-mapper device. Since dm devices are not partitionable it
fails with EINVAL.

> partx: /dev/dm-0: adding partition #2 failed: Invalid argument
> partx: /dev/dm-0: error adding partitions 1-2

The partx program comes from the util-linux package:

$ qwhich partx
util-linux-2.24.2-1.fc20.x86_64

You're probably looking for kpartx which is part of multipath-tools. On
Red Hat distros it's in a separate sub-package named kpartx:

$ qwhich kpartx
kpartx-0.4.9-56.fc20.x86_64

The kpartx command reads partition data from the disk and creates
device-mapper linear maps corresponding to each discovered partition.
This allows you to access the partitions on a device-mapper device as
separate dm devices (e.g. you'd get devices with paths like
'/dev/mapper/dm-0p1' or whatever depending on the -p switch given).

Most distros today will automatically run kpartx when new multipath
devices appear or when they change so you shouldn't need to run it
manually all the time.

Regards,
Bryn.

Re: partx fails 4096 block size

[Ross Anderson]

Bryn,

Let me first say thank you for a very detailed reply. I apologize for 
misunderstanding the multi path scheme and partx vs kpartx. After 
reading the information provided I still have an outstanding issue. 
kpartx works as expected when called manuall. The rules provided inside 
the git pull kpartx.rules are in the udev path.  I still experience a 
lack of partition creation. Udev debug shows the lun dm devices being 
created. My question is does udev call kpartx or is there some trigger 
within multipath? I do see the feature no_partition located in the git 
example conf file. I checked my conf and found no such setting. I'd 
appreciate any suggestion as to if this is a udev or mpath issue.

http://pastebin.com/K3VBtzAG

Thanks again for everyone's time reading this.

Ross

On 9/16/2014 3:52 AM, Bryn M. Reeves wrote:
> On Mon, Sep 15, 2014 at 02:48:23PM -0500, Ross Anderson wrote:
>> I'd appreciate any help in troubleshooting this. Quiet frustrating not being
>> able to use mpath on 4k blocks.
> Doesn't seem related to sector size.
>   
>> http://pastebin.com/EbTMXdvE
>> ###partx -a-v
>> partition: none, disk: /dev/dm-0, lower: 0, upper: 0
>> /dev/dm-0: partition table type 'gpt' detected
>> partx: /dev/dm-0: adding partition #1 failed: Invalid argument
> partx is trying to call a BLKPG partition management ioctl on a
> device-mapper device. Since dm devices are not partitionable it
> fails with EINVAL.
>
>> partx: /dev/dm-0: adding partition #2 failed: Invalid argument
>> partx: /dev/dm-0: error adding partitions 1-2
> The partx program comes from the util-linux package:
>
> $ qwhich partx
> util-linux-2.24.2-1.fc20.x86_64
>
> You're probably looking for kpartx which is part of multipath-tools. On
> Red Hat distros it's in a separate sub-package named kpartx:
>
> $ qwhich kpartx
> kpartx-0.4.9-56.fc20.x86_64
>
> The kpartx command reads partition data from the disk and creates
> device-mapper linear maps corresponding to each discovered partition.
> This allows you to access the partitions on a device-mapper device as
> separate dm devices (e.g. you'd get devices with paths like
> '/dev/mapper/dm-0p1' or whatever depending on the -p switch given).
>
> Most distros today will automatically run kpartx when new multipath
> devices appear or when they change so you shouldn't need to run it
> manually all the time.
>
> Regards,
> Bryn.
>
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel