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Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

 
Server-Support
Super Advisor

Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

People,

I'm using HPE Lefthand P4530 G2. My currentFree unused array is just 1620 GB, since I'm using RAID-10 (2-way) so effectively it is just 810 GB available.

Since my backup software using Storage Array Snapshot as per this article: https://helpcenter.veeam.com/docs/backup/vsphere/backup_from_storage_snapshots_hiw_hp.html?ver=95

Therefore based on this discussion: https://forums.veeam.com/veeam-backup-replication-f2/lefthand-snapshots-t20207.html

I have been told by the support team to use Thin LUN to utilize the Storage Snapshot with less disk space usage.

  1. My current LUN for all VMware VMs are on Thick LUNs to avoid over-provisioning, so what're the steps to convert it back to Thin LUN with no data loss ?
  2. Does the converted LUN will be reduced in size or will it be at the same capacity as it is now ?

Thanks,

Best regards,
12 REPLIES 12
giladzzz
Honored Contributor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

Hi

just right click your volume 

edit volume > advanced  > change from full to thin

this is done online reclaimed space will depend on the actual data in 

VMware and if you have space reclamation.

you can also create a new thin provisioned datastore and do storage vmotion from one datastore to the other

Regards

 

Stor_Mort
HPE Pro

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

Keep in mind that HPE does not recommend going above 95% cluster utilization as the cluster needs some scratch space, particularly when space reclamation is enabled.

I am an HPE employee - HPE SImpliVity Support

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Server-Support
Super Advisor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

Hi All,

Thanks for the reply.
Does the unused space will be released back to the storage pool or will it be the same free space I see currently due to thick provisioned ?

How can I turned off the space reclamation ?
I do not want to cause any issue when the free disk space is fall below 5% since I will be using backup software that utilise storage snapshot..
Best regards,
Stor_Mort
HPE Pro

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

Yes, unused space is returned to the cluster pool.

Check if space reclamation is turned on by clicking on the management group icon in the navigation menu and looking at the details tab. Once it has been enabled, it cannot be turned off.

I am an HPE employee - HPE SImpliVity Support

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Server-Support
Super Advisor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

Lefthand CMCLefthand CMC

Hi @Stor_Mort I cannot see it enabled on the above?

Best regards,
Server-Support
Super Advisor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

P4530G2P4530G2

I've also checked in another management group today, it was up to 95% disk utilized, luckily no issue at the VMware side due to LLUNbecoming read only ?

Best regards,
Server-Support
Super Advisor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

ok,
I've successfully converted the Thick LUN to Thin LUN on the fly with no issue since the storage is not overprovisoned in Thick LUN.

Does anyone know what would happens if it is the other way around ?

Overprovisoned Thin LUN converted to Thick ?
Would there be any disaster ?
Best regards,
Stor_Mort
HPE Pro

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

The system will not allow you to create a fully-provisioned volume that is larger than the available cluster space. However, it will let you make one that uses more than 95% but less than 100% of the available cluster space, which is a situation you should avoid.

I am an HPE employee - HPE SImpliVity Support

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oikjn
Honored Contributor

Re: Lefthand P4530 G2 Converting Thick LUN to Thin steps and caveats ?

I suggest that you create one THICK LUN that is something like 50GB in size that you do not connect to anything.  Then if you are not paying attention to your SAN capacity and suddenly you run out of space, all your LUNs will go into read-only mode and you can quickly recover simply by deleting that one thick LUN.  the 50GB is arbitrary, you might want it to be larger to give you a larger buffer if you need more time to react to order more storage if needed based on your normal data growth rate. 

If you run out of space on your SAN, all LUNs go into read-only mode until space is freed up and the only way to free up space is delete LUNs or delete snapshots since write access to all LUNs are removed which can lead to a nasty chicken/egg situation if you aren't prepared with that trash LUN I mentioned above.