ME4024 tiered storage with vmware datastores?

Hello @ak_brian,

A pool will contain multiple disk groups and will have at least 2 disk groups per pool if 2 different kinds of disk are used. With automated tiered storage(ATS) the cold pages/ blocks will move to slower disk to preserve your higher tier drives for frequently accessed data. The ME4024 uses one virtual pool per controller, so, using virtual storage mode, the tiering is done at POOL level, not LUN level.

When you deploy a ME4024 the best practices is to create two virtual pools (one per controller to balance the load),  since you have SSD and HDD, the storage will probably recommend to create one pool with SSD and a second pool with only HDD, so, you will have one tier (performance) on controller A (virtual Pool A), and only standard tier on the controller B (virtual pool B). 

Here is a link to the administrator guide and if you look on page 23 it explains how Tiering is handled.  https://dell.to/39GW8OY

Here is also a link to Dell EMC PowerVault ME4 Series and VMware vSphere best practices.
https://dell.to/39GW9T2

Regards.

You create two separate virtual disk groups one for SSD and one for mechanical drives and the auto tiering will move data to the SSDs based on access patterns.

Hi @DiegoLopez 

Thanks for the reply, sorry I'm late getting to it.

I guess I'm still confused by this, it's my first time using an ME4, in other SAN solutions with mixed/hybrid drives when I go to create a volume it allows me to assign both drive types to it in one volume to ensure tiered performance.

In the ME4 I guess I'm being thrown that it won't allow me to make a single volume with both pools - it will let me make a volume, or virtual volume technically, but if I try to utilize both pools it indicates it will create two volumes. I've read on how affinity works, but I'm just not understanding how volumes work or something.  If the tiering is happening at the pool, how does the volume know to tier if the volume won't let me select both disk types?  Or put another way:  If I make a single virtual volume of 1TB, using Pool A (HDD) only, how does it tier?  If that happens only in the background outside of the volume and at the Pool, should I never make a volume using Pool B (SSD) so they always have space for tiering?

Thanks

Hi,

Thanks for the response, and I hate to keep circling around this, but I just want to confirm what you're saying:  It does the tiering automatically in the pools, but when I create a volume, do I make it using Pool A (HDD's) or Pool B (SSDs)?  I can do both, but as shown in the picture it just makes two separate volumes instead.  Do I only use the HDD pool and not add the SSDs ever?  Ie: leave the SSDs out of any volume I create so that the array can move HDD data into the SSD pool as needed?

Hello,

Auto-tiering takes place only within the same pool, pool A and pool B wouldn't interact with one another. If you set up a Pool A with an HDD disk group and an SSD disk group, then the auto-tiering move between them. You can then use set the tier affinity to your needs.

Okay, that's making more sense.

After reading this: https://www.dell.com/support/kbdoc/en-us/000179811/powervault-me4-how-to-create-a-virtual-disk-group-with-me-storage-manager-gui

It looks like I messed up accepting the default pool recommendations instead of using the Advanced Configuration - which looks like I could have manually created my mixed pools.  I also can't seem to delete the pools it created despite seeing a "remove" option in storage setup, so I'm going to have to figure out how to reset it completely to factory and start over.

Thanks for the help.