[Linux-cluster] Unformatting a GFS cluster disk

[Wendy Cheng]

chris barry wrote:
> On Wed, 2008-03-26 at 10:41 -0500, Wendy Cheng wrote:
>   
>> DRand at amnesty.org wrote:
>>     
>>> ......The disk was previously a GFS disk and we reformatted it with 
>>> exactly the same mkfs command both times. Here are more details. We 
>>> are running the cluster on a Netapp SAN device.
>>>       
>> Netapp SAN device has embedded snapshot features (and it has been the 
>> main reason of choosing NetApp SAN devices for most of the customers). 
>> It can restore your previous filesystem easily (just few commands away - 
>> go to the console, do a "snap list", find your volume that hosts the lun 
>> used for gfs, then do a "snap restore"). This gfs_edit approach (to 
>> search thru the whole device block by block) is really a brute-force way 
>> to do the restore. Unless you don't have "snap restore" license ?
>>     
>
> Wendy,
>
> We too are using a NetApp. There was talk amongst out IT group that
> these snaps would not work against a raw lun.
>   

Have you (or IT group) talked to Netapp NGS folks ? I personally don't 
know whether there is a specific document talking about the interaction 
between GFS and Netapp SAN. However, remember that Netapp SAN does its 
snapshots on its volume(s). Now assume you export /vol/vol1/lun1 via FCP 
or ISCSI that is seen by Linux box as /dev/sda, then, the volume 
snapshots lists can be found via "snap list" command, if you do have 
proper licenses in place.

-- Wendy

> Can you point me at any docs that describe how best to implement snaps
> against a gfs lun?
>
>
>
> Regards,
> -C
>
> --
> Linux-cluster mailing list
> Linux-cluster at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-cluster
>