[CentOS] data recovery

[Ross Walker]

On Sep 26, 2011, at 11:18 AM, Paras pradhan <pradhanparas at gmail.com> wrote:

> Hi Lamar,
> 
> On Mon, Sep 26, 2011 at 5:53 AM, Lamar Owen <lowen at pari.edu> wrote:
>> On Friday, September 23, 2011 04:29:39 PM Paras pradhan wrote:
>>> This is a SAN drive mounted. I have checked with my storage
>>> administrator if this has been re mapped or any similar events and he
>>> verified that nothing has happened...(I trust him)
>> 
>> May I ask what sort of SAN?  Fibre Channel or iSCSI?  Are there any access controls (such as EMC's Access Logix or zoning in the switch) in place to prevent multiple initiators connecting to a particular LUN?
> 
> Its a Hitachi OpenV fibre channel SAN (4Gbps HBA). My storage admin
> checked if this LUN can be accessible by others and he found no other
> hosts have access to it.
> 
>> 
>> SAN attachment mildly complicates things; I've seen some odd LUN reshuffling before, but it was an older FLARE than what I'm currently running on our Clariions and it was something that was a corner case but was fixed in a later NDU, and it had to do with Access Logix (I don't remember the Primus number right off, as it has been several years now).
> 
> reshuffling here means automatically changing disk's geometry as I am
> having an issue? It would be interesting to know if this can happen.
> 
>> 
>> If the SAN OS keeps event logs you could try to correlate with the event; beyond that you may just have to do some testing.
>> 
>> As you say, someone somewhere had to do a repartition; the hard part is determining where the error is.  Good luck.
> 
> 
> Here are some new additional info :
> 
> My colleague mounted this LUN to a different host and we found the
> same partitions over there too which is normal.
> 
> I dd a 1st device to a file and opened the image file with bvi and
> found some hosts name, VG name etc etc. in there. Then he ran a
> recovery tool (R studio) in all three devices and was able to recover
> most of this data.
> So my question is: if the LUN has been re partitioned for ex: say to
> install windows , why am i seeing our data in these newly created
> partitions? Is it possible to see data in a reapportioned drive?

Might it be possible you ran KVM on the host and accidentally set the guest disk to /dev/sda?

-Ross