[Ocfs2-devel] why oracle give up dlm by disk on ocfs2? because performance?

[Jensen]

On 2013/7/4 0:42, Srinivas Eeda wrote:

> On 07/03/2013 01:28 AM, Jensen wrote:
>> On 2013/7/3 13:06, Jeff Liu wrote:
>>
>>> On 07/03/2013 09:27 AM, Jensen wrote:
>>>
>>>> On 2013/7/3 1:20, Mark Fasheh wrote:
>>>>
>>>>> On Tue, Jul 02, 2013 at 10:07:52AM +0800, Jensen wrote:
>>>>>> On 2013/7/2 9:35, Sunil Mushran wrote:
>>>>>>
>>>>>>> A general purpose file system requires one to manage over a million locks concurrently. So performance is the main reason.
>>>>>>>
>>>>>> Thanks for your comments.
>>>>>>
>>>>>> Has Oracle compared the performance between ocfs2 and ocfs1?
>>>>> Firstly, that's implied in the answer you just got. Also, who wouldn't
>>>>> compare performance from one version of a file system to the next?
>>>>>
>>>>> Can you please cut to the chase and either ask what you really want to know
>>>>> or make the statement you're trying to make so we can move on?
>>>>>
>>>>
>>>> Thanks for your answer.
>>>> we want to use compare and write scsi command to replace DLM module. it is similar
>>>> with vmware vmfs.
>>>>
>>> I'm not trying to answer this question.
>>>
>>> I knew that OCFS2 is deployed in HuaWei.com in a large-scale cluster up
>>> to 128 nodes, so I'm not very much surprised at something you mentioned
>>> below, but...
>>>
>>>> why we want to replace dlm in ocfs2? because:
>>>> 1. The stability of ocfs2 dlm is very poor, we found 100+ bug.
>>> That sounds interesting, how to classify those problems?
>>> - Fatal error, panic
>>> - Result in an interruption in service
>>> - Wrong results, but can work around?
>>> - Trivial
>>>
>>> Reporting bugs to bugzilla/OCFS2 would be useful to keep track of them:
>>> https://oss.oracle.com/bugzilla/
>>>
>>
>> Recently, Huawei has send many bug to open source community.
> Yes and we appreciate your contributions :)
>>   which bug exist in
>> open source. other change or bug belong to enforce ocfs2 function ,for example, when disk
>> timeout, open source code will reboot the machine, we modify it, we set the ocfs2
>> invalid(can't read and write), open source may not interesting with those modify.
> Can you please point me to these patches, I would be very interested to 
> look at. If the patches are safe for all kind of workloads and guarantee 
> to stop in-flight i/o's then it makes sense to add them to mainline ocfs2.
>>
>>> Thanks,
>>> -Jeff
>>>
>>>> 2. The Reliability of ocfs2 dlm is very poor, especially in network split, the
>>>>     worse case split two domain, the half of node must be reboot.
> Currently we are looking into this. It appears that most of the network 
> issues we are seeing may not really caused by network layer. They are 
> mostly false errors because o2net thread got busy. Once this happens, in 
> some scenarios reconnect always fails which is a bug. If you are 
> currently running into these problems please share so we can analyse them.
>>>> 3. the maximum number of mounted machine is 32, we want to support more.
>>>>
>>>> currently we worry about two thing:
>>>> 1. The performance lock and unlock. because it use the scsi command and it is similar with IO read and write.
>>>> 2. The change is very very large. because it maybe modify the disk layout of ocfs2.
> I am just curious, have you already made these changes? Are the changes 
> scalable?

we had not made these changes. we plan to change this.

>>>>
>>>> so anyone interested with this?
>>>>
>>>>> Thanks,
>>>>> 	--Mark
>>>>>
>>>>> --
>>>>> Mark Fasheh
>>>>>
>>>>>
>>>>
>>>>
>>>>
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>>>
>>>
>>>
>>
>>
>>
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