Re: ASM bug?
- From: Andrew Kerber <andrew.kerber@xxxxxxxxx>
- To: Stefan Koehler <contact@xxxxxxxx>
- Date: Thu, 2 Oct 2014 10:56:20 -0500
I am pretty sure the labels she mentions and the disk scanning are the ASMLIB
methods
Sent from my iPhone
> On Oct 2, 2014, at 10:26 AM, Stefan Koehler <contact@xxxxxxxx> wrote:
>
> Hi Andrew,
> for sure - is she using ASMLIB?
>
> I may have missed some posting about that, otherwise Maureen may provide this
> information in addition later on. However the persistent device naming
> (multipath binding) is also needed / recommended with ASMLIB (scan order). I
> personally would go for udev anyway :-))
>
> Best Regards
> Stefan Koehler
>
>> Andrew Kerber <andrew.kerber@xxxxxxxxx> hat am 2. Oktober 2014 um 17:06
>> geschrieben:
>>
>> 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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