What’s New in Core Storage in vSphere 6.7 Part V: Rate Control for Automatic VMFS UNMAP

vSphere 6.7 core storage “what’s new” series:

VMware has continued to improve and refine automatic UNMAP in vSphere 6.7. In vSphere 6.5, VMFS-6 introduced automatic space reclamation, so that you no longer had to run UNMAP manually to reclaim space after virtual disks or VMs had been deleted.

Continue reading What’s New in Core Storage in vSphere 6.7 Part V: Rate Control for Automatic VMFS UNMAP

ESXi iSCSI, Multiple Subnets, and Port Binding

With the introduction of our Active-Active Synchronous Replication (called ActiveCluster) I have been getting more and more questions around multiple-subnet iSCSI access. Some customers have their two arrays in different datacenters, and also different subnets (no stretched layer 2).

With ActiveCluster, a volume exists on both arrays, so essentially the iSCSI targets on the 2nd array just look like additional paths to that volume–as far as the host knows it is not a two arrays, it just has more paths.

Consequently, this discussion is the same as if you happen to have a single array using more than one subnet for its iSCSI targets or if you are using active-active across two arrays.

Though there are some different considerations which I will talk about later.

First off, should you use more than one subnet? Well keeping things simple is good, and for a single FlashArray I would probably do that. Chris Wahl wrote a great post on this awhile back that explains the ins and out of this well:

http://wahlnetwork.com/2015/03/09/when-to-use-multiple-subnet-iscsi-network-design/ 

Continue reading ESXi iSCSI, Multiple Subnets, and Port Binding