[Ocfs2-users] mixed mode mount options?

[Sunil Mushran]

ro is just a mount option which has no affect on the cluster. Well,
the only time it affects is when the device is a read-only media
in which case the mount detects it and mounts the volume hard-ro.
In that case, the cluster stack is automatically skipped.

For normal ro mounts, you can change it on the fly like with any
file system.

To change from ro to rw, do:
# mount -o remount,rw /mntpath

Back again:
# mount -o remount,ro /mntpath

Billy wrote:
> Can I safely assume that the only difference between a ro node and a rw node in the same cluster is the "ro" or "rw" switch in /etc/fstab upon mount (we are using Redhat)?  If a ro node crashes, will it be fenced off the cluster just like a rw node causing a brief jitter?  Any doc that you can refer me to for details?  Thank you for your help!
>
>
> Billy
>    
>
> --- On Sun, 12/6/09, Sunil Mushran <sunil.mushran at oracle.com> wrote:
>
>   
>> From: Sunil Mushran <sunil.mushran at oracle.com>
>> Subject: Re: [Ocfs2-users] mixed mode mount options?
>> To: "Billy" <lfl2000us at yahoo.com>
>> Cc: "ocfs2-users at oss.oracle.com" <ocfs2-users at oss.oracle.com>
>> Date: Sunday, December 6, 2009, 12:48 PM
>> The node doing the ro mount is a full
>> member of the cluster. Yes, it will participate in cluster
>> activities including replaying a dead node's journal, etc.
>> So it is not the spectator node that gfs2, I believe, has.
>> I've never quite understood how a spectator node can
>> maintain cache coherencies.... other than by disabling all
>> caches and hitting disk on every read. Not sure if gfs2 does
>> that or what level of coherency it guarantees the user.
>>
>>
>> On Dec 6, 2009, at 9:14 AM, Billy <lfl2000us at yahoo.com>
>> wrote:
>>
>>     
>>> Thank you Sunil!
>>>
>>> Is there any difference in setup for a ro node vs. rw
>>>       
>> nodes?  In other words, will a ro node be a member of
>> the cluster and sending/receiving heartbeat?  I would
>> image a ro node should not affect the cluster in any way
>> should the node fail/crash, but I am not sure if it is
>> correct.
>>     
>>> Billy
>>>
>>> --- On Fri, 12/4/09, Sunil Mushran <sunil.mushran at oracle.com>
>>>       
>> wrote:
>>     
>>>> From: Sunil Mushran <sunil.mushran at oracle.com>
>>>> Subject: Re: [Ocfs2-users] mixed mode mount
>>>>         
>> options?
>>     
>>>> To: "Billy" <lfl2000us at yahoo.com>
>>>> Cc: ocfs2-users at oss.oracle.com
>>>> Date: Friday, December 4, 2009, 5:11 PM
>>>> Billy wrote:
>>>>         
>>>>> Does anyone know if OCFS2 supports mixed
>>>>>           
>> mounts?
>>     
>>>> We have 4-node OCFS2 cluster, is it possible for
>>>>         
>> one node to
>>     
>>>> mount read only and the other 3 nodes mount -rw on
>>>>         
>> a same
>>     
>>>> volume?
>>>>         
>>>> Sure.
>>>>
>>>>         
>>>
>>>       
>
>
>       
>