[BlueOnyx:04483] Re: Curious read only filesystem behaviour with SANs

[Gerald Waugh]

On Fri, 2010-05-14 at 10:01 +0100, Jeff Jones wrote:
> Hi guys,
> 
> This is probably more of a CENTOS issue than a BX one - but I thought I'd ask about it just in case anyone else has seen this / knows a fix.
> 
> We have a couple of BX servers running through a VM hypervisor, and the VM is connected to a SAN. So BX gets it's iSCSI LUNs from the SAN via the VM.
> 
> We have Windows servers on this VM, as well as these BX servers.
> 
> Whenever we have an issue with the SAN, and the storage cluster fails over to it's mirror, most of the BX servers for some reason get placed into 'READ ONLY' mode.
> 
> We've never had this issue with Windows servers strangely. 
> 
> Anyone seen this happen before?
> 
> The remedy is to reboot the BX server, after reboot it goes back to read/write. Is there any other way of going back to R/W mode without having to reboot?
> 
> Also is there any way of adjusting the READ only mode so that it's either less sensitive, or goes back to R/W by itself?
> 
> Cheers,
> 
For instance to remount /dev/md0 rw

  mount /dev/md0 -o remount,rw

Gerald