EMC & VMware: Extending QoS from Server Layer to IO Layer

[trilivas]

This doesn't make much sense for VMFS. In fact it makes NO sense at all given that QoS is applied at the LUN level and a VMFS LUN typically holds several VMDKs.

So if you apply QoS at the array Level you're impacting ALL the VMDKs on the that VMFS.

The ONLY area this would work is for RDM where each LUN is associated with a VM.

Frankly, no news here...a lot of storage vendors can do QoS at the LUN level. Nothing earth shattering here...just marketing.

[achais72]

Customers should use best practices - datastore (VMFS or NFS) layout with different tiers. You can apply the QoS at those tiering levels to VMs by class, but 1:1 mapping is also possible. Some vendors have storage QoS - some better(EMC, 3PAR and Compellent), some worse(like Flexshare from NetApp), and all implement differently. Customers should look at each vendor and decide. The key for VMware use is to be able to apply at the container, and use DRS-like rules (limits, reservations)