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 Post subject: Quick snapshot question
PostPosted: Wed Nov 01, 2017 5:29 pm 

Joined: Wed Oct 30, 2013 2:30 pm
Posts: 242
So... Sorry for the dumb question.

I am playing with snapshots in SSMC. I am able to snapshot a lun just fine. But when I go to promote the snapshot back to the base VV, I get an error that the operation cannot be performed because there are no valid targets.

Anyone seen this in SSMC before and can tell me what dumb thing I'm doing that is keeping me from rolling back the snapshot to the base VV?


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 Post subject: Re: Quick snapshot question
PostPosted: Thu Nov 02, 2017 3:42 am 

Joined: Tue Mar 29, 2016 9:32 pm
Posts: 45
Is the volume still exported to a host when you try to promote the snapshot ? Because that would block it.


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 Post subject: Re: Quick snapshot question
PostPosted: Thu Nov 02, 2017 10:14 am 

Joined: Wed Oct 30, 2013 2:30 pm
Posts: 242
Bingo...

I had been trying to avoid that since the lun is an RDM through a VMware host to a VM and just didn't want to deal with that slight hassle but unexporting it did the job.

Thanks!


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 Post subject: Re: Quick snapshot question
PostPosted: Thu Dec 21, 2017 3:04 am 
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Joined: Thu Oct 26, 2017 1:21 am
Posts: 34
is it posible to promote snapshot using online option even if base volume is exported?

From the documentation, page 24. https://h20195.www2.hpe.com/v2/GetPDF.a ... 486ENW.pdf

"There are task needed to be taken from the host operating system to perform the operation successfully". what task??


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 Post subject: Re: Quick snapshot question
PostPosted: Thu Dec 21, 2017 4:22 am 

Joined: Wed Nov 19, 2014 5:14 am
Posts: 476
Yes but if you change the underlying data on the volume at the array level by promoting a snapshot the host will have no knowledge of this and it would likely lead to data corruption. The reason being the hosts cached index of the file system and what resides on the disk after the promote will be completely different.

Different O/S's and filesystems have different capabilities but typically you would need to unmount the file system (drive letter) at the host and then remount after the promote has completed, at which point the host would re-read the file allocation table and understand the changes that were made by the promote.

In terms of effort to unpresent and represent vs unmount and remount they're probably pretty similar unless you have a complex environment.


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