IO error issues with MD3000i on Linux

[Bryan]

In that case there shouldn't be.  I wanted to point out if multiple
hosts were accessing the same lun/virtual disks you would end up with
corruption.  The LUN number is presented to hosts.  It is usually
checked by cluster implementations (ESX 3.x uses the host id as one
check to determine if storage is presented identically across multiple
hosts).  In non-cluster environments the value isn't used since it's
assumed that each host has unique access to its storage.

On 6/14/09, morten at nidelven-it.no <morten at nidelven-it.no> wrote:
> Bryan,
>
> Yeah.. But if I have one host for each virtual disk, and one unique
> initiator (all defined in the md3000i) - why should there be a problem? As
> far as I can tell, no two servers should be able to access the same virtual
> disk.
>
> Does setting the LUN number in the md3000i software affect anything? If so,
> why aren't there checks for that?
>
> -Morten
>
> -- oppr. melding --
> Emne: Re: IO error issues with MD3000i on Linux
> Fra: Bryan <bryan.madhatter at gmail.com>
> Dato: 14.06.2009 16:07
>
> It matters what hosts can access a lun since without something in the
> OS to control file locking there is a high probability of eventually
> corrupting your data.
>
> On 6/14/09, Morten W. Petersen <morten at nidelven-it.no> wrote:
>> Matthew Geier skrev:
>>> morten at nidelven-it.no wrote:
>>>> Hi,
>>>>
>>>> I have two SAN-clients accessing the MD3000i.  The first client
>>>> works just fine, but the second does not.
>>>>
>>>> I think I configured them similarly on the first and second server,
>>>> so I'm thinking something is wrong.
>>>>
>>>>
>>> You are not trying to access the same LUN from both are you ?. I'm not
>>> sure the MD3000i supports shared file systems.
>>
>> The same LUN?  Well, it might be that some of the host-to-virtual-disk
>> mappings
>> had the same LUN - but I didn't know that mattered?  I see there are 4
>> "Access"
>> disks mapped to different hosts which all have the LUN 31.
>>
>> I've got 3 virtual disks setup now, each has its own host with an iSCSI
>> initiatior.
>>
>> One interesting thing;  I got an IO Error message when using the first
>> controller,
>> but not on the second!
>>
>> -Morten
>>
>> --
>> Morten W. Petersen
>> Manager
>> Nidelven IT Ltd
>>
>> Phone: +47 45 44 00 69
>> Email: morten at nidelven-it.no
>>
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>
>