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Datastore vs LUN
Have been trying to differentiate (block) Datastores and LUN's. What's the difference beyond the Datastore VMware integration?
The VMware integration with Datastores is a time saver by automatically putting a filesystem on the block device, and rescanning the host bus to pick up the new datastore. Another benefit is having consistent naming across the environment (not that VMware can't rename the datastore and put a new label on it...).
The "traditional" VMFS on LUN loses the time savings and consistent naming.
Considering the benefits of Datastores, what are the use cases for LUN over Datastore for VMware storage? The biggest case that comes to mind is where there's existing workflow/automation for LUNs.
mbraak
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October 17th, 2017 06:00
The benefits are also the biggest flaws.
Each change on a datastore like assigning one to a host will result in rescan and vmfs rescan on the esx host.
Imagine the situation where you add a new esx host and need to assign 25 vmware datastore luns to it.
You can only add them one by one cause the gui (and also cli) wont allow you to select multiple luns when assigning vmware datastores to hosts and each addition will kick of 2 rescans (HBA rescan and VMFS rescan) and a storage system refresh on the esx hosts.
So simple math 25x3 = 75 operations on the ESX host.
With lun mode you can assign the 25 luns to the hosts and perform a single rescan to complete.
Still missing the "Storage Groups" of the VNX/Clarion systems. Dont understand why they decided to not implement such a basic and vital feature
tsamuel0905
136 Posts
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October 22nd, 2017 01:00
how about VVols