Robsoncb
Contributor
Contributor

Rescan for datastore is Dangerous ?

Hi Guys,

I configure a new datastore on my storage dell equalogic to vmware. But i don´t see it.

I think, I have to do a Rescan for datastore, but i´m afraid for it stop my virtual machines.

It´s Dangerous to do IT ?

7 Replies
virtualg_uk
Leadership
Leadership

There is no impact in re-scanning a for new datastores.


Graham | User Moderator | https://virtualg.uk
rcporto
Leadership
Leadership

It depends... I already get some situation where a simple rescan cause some downtime on SAN due the storage array of the customer was in the overload condition and was not able to handle the rescan of all hosts in the cluster at the same time. But, if your storage array is not overloaded, you can do this safely.

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Richardson Porto
Senior Infrastructure Specialist
LinkedIn: http://linkedin.com/in/richardsonporto
virtualg_uk
Leadership
Leadership

You could just rescan one host at a time to mitigate against such risk. Never seen it myself though.


Graham | User Moderator | https://virtualg.uk
Teddy092
Enthusiast
Enthusiast

I'm never seen any interruptions by doing a rescan.

However ,I would agree with Richardson in the case where a overloaded storage array could cause some downtime while rescaning datastores.

If the Storage is fine, you can go ahead.

Regarding the main issue I have some questions.

- Was the Equalogic array already used to provision storage to your vSphere environnement ?

  - If not, make sure that both your the equalogic and your ESXi(s) can see each other.

  - If yes, have you follow the proper precedure to add a new datastore

If you found this or any other answer useful please consider the use of the Helpful or Correct buttons. Many thanks.
Robsoncb
Contributor
Contributor

Ok,

I configure other Lun on Equalogic, with the same config that other that is conected to the Vmware with IP adress connect.

But, I don´t see the LUN in Vmware options, when I click in "Add a Datastore".

I Think that was because I don´t do a Rescan for Datastore in Vmware.

- The proper procedure is: Rescan for a new datastore and configure it ok ?

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virtualg_uk
Leadership
Leadership

Correct, once the LUn is created on the SAN and the host has permission to see it (Via storage group for example) then you need to rescan one of the hosts and then you'll see the LUN when selecting Add a Datastore


Graham | User Moderator | https://virtualg.uk
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Teddy092
Enthusiast
Enthusiast

If you provisioned LUN from your Equalogic in the past, then it should be fine by directly re-scanning for new datastore.

Please make sure to check both option before re-scanning.

If you found this or any other answer useful please consider the use of the Helpful or Correct buttons. Many thanks.
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