Re: ASM bug?
- From: Andrew Kerber <andrew.kerber@xxxxxxxxx>
- To: "contact@xxxxxxxx" <contact@xxxxxxxx>
- Date: Thu, 2 Oct 2014 10:06:02 -0500
Sounds like a bug. If she is using ASMLIB, she does not use Udev. The two are
mutually exclusive.
Sent from my iPhone
> On Oct 2, 2014, at 2:53 AM, Stefan Koehler <contact@xxxxxxxx> wrote:
>
> Hi Maureen,
> that's no bug. You have to use persistent device naming (multipath binding)
> by multipathd and udev rules to set the correct device permission / owner.
>
> However be aware of the suggested multipath settings by every storage vendor
> (e.g. fail_if_no_path with NetApp) and ASM. In some cases you are not able to
> flush the device map due to such suggestions after a path failure, even if
> the disk is not used by ASM anymore.
>
> Best Regards
> Stefan Koehler
>
> Oracle p erformance consultant and researcher
> http://www.soocs.de
>
>> Maureen English <maureen.english@xxxxxxxxxx> hat am 2. Oktober 2014 um 02:34
>> geschrieben:
>>
>> device-mapper-multipath
>>
>>
>>> On 10/1/2014 4:27 PM, Dimensional DBA wrote:
>>> What Multipathing SW are you using?
>>>
>>> Matthew Parker
>>> Chief Technologist
>>> 425-891-7934 (cell)
>>> Dimensional.dba@xxxxxxxxxxx
>>> View Matthew Parker's profile on LinkedIn
>>>
>>>
>>> -----Original Message-----
>>> From: Dimensional DBA [mailto:dimensional.dba@xxxxxxxxxxx]
>>> Sent: Wednesday, October 01, 2014 5:23 PM
>>> To: 'maureen.english@xxxxxxxxxx'; 'oracle-l@xxxxxxxxxxxxx'
>>> Subject: RE: ASM bug?
>>>
>>> Did you put the disk id's in the multipath.conf file which hard sets the
>>> mapping?
>>>
>>>
>>> Matthew Parker
>>> Chief Technologist
>>> 425-891-7934 (cell)
>>> Dimensional.dba@xxxxxxxxxxx
>>> View Matthew Parker's profile on LinkedIn
>>>
>>>
>>> -----Original Message-----
>>> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
>>> On Behalf Of Maureen English
>>> Sent: Wednesday, October 01, 2014 4:44 PM
>>> To: oracle-l@xxxxxxxxxxxxx
>>> Subject: ASM bug?
>>>
>>> We're building a new system and the sysadmin and dba working on it
>>> discovered a problem.
>>> This is RHEL5 and Oracle 11.2.0.4 RAC.
>>>
>>>> At boot, or when instructed to do so, Oracle ASM scans disks and
>>>> creates an index of which ASM labels are on which disks, however it
>>>> does not do anything to tell the kernel that it intends to use the disks
>>> it has identified. It is not until ASM mounts the disks in a diskgroup that
>>> it marks them as "in use".
>>>> Until a disk is actually in use (opened), the kernel will happily
>>>> unmap or re-map dm devices that Oracle ASM has already scanned. Oracle
>>>> ASM will try to modify the wrong disk if the kernel remaps an unused dm
>>> device to a different disk before ASM mounts it.
>>>> When multipath is run with the -F option, it will flush all multipath
>>>> devices that are not in use. When multipath re-maps the devices, it
>>>> may assign different device numbers to the disks it flushed. There is
>>>> no way to tell Oracle ASM to forget about a label it has scanned
>>>> without deleting the ASM labels off the disk or rebooting the system. It
>>> is very important not to flush a disk that ASM has already identified. Do
>>> not use multipath -F if there are any unmounted ASM disks presented to the
>>> system.
>>>
>>> Is this a known bug, or are there some rules regarding ASM and multipath
>>> that we missed?
>>>
>>> I'm not actually working on this system, but thought it sounds like
>>> something others would have encountered. I'm still searching through
>>> Metalink docs....
>>>
>>> - Maureen
>>>
>>> --
>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>
>> --
>> Maureen English
>> Lead Database Administrator
>> University of Alaska
>> Fairbanks, AK
>> (907) 450-8329
>
>
>> -- //www.freelists.org/webpage/oracle-l
> -- //www.freelists.org/webpage/oracle-l
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