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

From: Jeff Liu <jeff.liu@oracle.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] why oracle give up dlm by disk on ocfs2? because performance?
Date: Wed, 03 Jul 2013 13:06:43 +0800	[thread overview]
Message-ID: <51D3B163.4000308@oracle.com> (raw)
In-Reply-To: <51D37DF0.1010704@huawei.com>

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/

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