Re: ASM bug?

From: Andrew Kerber <andrew.kerber_at_gmail.com>
Date: Thu, 2 Oct 2014 17:15:51 -0500
Message-Id: <B8AC2731-5D10-44B1-B943-241582E969A0_at_gmail.com>

It's been a while since I did this, but as I recall there is some guidance about the ASM disk string and exclude and include options with multi path. Did you verify all that?

Sent from my iPad

> On Oct 2, 2014, at 11:55 AM, Maureen English <maureen.english_at_alaska.edu> wrote:
>
> Stefan, Andew;
>
> Yes, we are using ASMLIB.
>
> - Maureen
>

>> On 10/2/2014 7:56 AM, Andrew Kerber wrote:
>> 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_at_soocs.de> 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_at_gmail.com> 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_at_soocs.de> 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_at_alaska.edu> 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_at_comcast.net
>>>>>>> View Matthew Parker's profile on LinkedIn
>>>>>>> 
>>>>>>> 
>>>>>>> -----Original Message-----
>>>>>>> From: Dimensional DBA [mailto:dimensional.dba_at_comcast.net] 
>>>>>>> Sent: Wednesday, October 01, 2014 5:23 PM
>>>>>>> To: 'maureen.english_at_alaska.edu'; 'oracle-l_at_freelists.org'
>>>>>>> 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_at_comcast.net
>>>>>>> View Matthew Parker's profile on LinkedIn
>>>>>>> 
>>>>>>> 
>>>>>>> -----Original Message-----
>>>>>>> From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
>>>>>>> On Behalf Of Maureen English
>>>>>>> Sent: Wednesday, October 01, 2014 4:44 PM
>>>>>>> To: oracle-l_at_freelists.org
>>>>>>> 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
>>>>>>> 
>>>>>>> --
>>>>>>> http://www.freelists.org/webpage/oracle-l
>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> Maureen English
>>>>>> Lead Database Administrator
>>>>>> University of Alaska
>>>>>> Fairbanks, AK
>>>>>> (907) 450-8329
>>>>> 
>>>>>  
>>>>>> -- http://www.freelists.org/webpage/oracle-l
>>>>> -- http://www.freelists.org/webpage/oracle-l

>
> --
> Maureen English
> Lead Database Administrator
> University of Alaska
> Fairbanks, AK
> (907) 450-8329

--
http://www.freelists.org/webpage/oracle-l

Received on Fri Oct 03 2014 - 00:15:51 CEST