In this post we will continue to discuss Implementing Complex Storage Solutions
here are the objectives from the blueprint that i am going to cover:
- Configure / Manage vSphere Flash Read Cache
- Create / Configure Datastore Clusters
Using VMware workstation:
- Microsoft Servers 2012R2 for Services (DNS , DHCP, etc…)
- installed esxi0 and esxi1
- Installed VCSA
- One VM installed on ESXi with VMware version 10 or higher
- Storage device that can support iSCSI ( i am using Netgear ReadyNAS 202)
- vSphere6 Storage Guide
- vSphere Resource Management
Configure / Manage vSphere Flash Read Cache:
Before we can start the lab we need to configure additional HDD for each ESXi so we can use for read cache, if you dont have an SSD drive you can mark the drive as flash .
Now lets add capacity to the Flash read cache on each of our ESXi’s , Click on the host >> Manage >> Settings >> Virtual Flash Resource Management >> Add Capacity and add the disk that we assign to it.
Perform the above task for the second ESXi and click refresh and review the details
Now you can start using the cache for read cache or even swap cache .
To assign flash read cache for a VM , got the VM setting and expend the Hard Disk settings , under virtual flash read cache you can just type the number of GB or click on advanced setting and also control the block size.
Note: you cannot assign cache more than the VM disk capacity.(I tried :-))
also when migrating VM to another hosts make sure the other host has flash cache enable and sufficient space.
Create / Configure Datastore Clusters:
To create a new datastore cluster , click on the storage icon , right click on the data center >> storage >> New Datastore Cluster
Next you need to name the datastore cluster and note that Storage DRS will be on
Next you can choose from Fully automated or no automation , the default is no automation.
Next you can set the utilized space threshold ,minimum free space IO latency threshold and some advanced options
Next choose the cluster
Choose the datastore for the datastore cluster
Storage DRS Anti-Affinity Rules:
You can create Storage DRS anti-affinity rules to control which virtual disks should not be placed on the same datastore within a datastore cluster. Antiaffinity rules are enforced during initial placement and Storage DRS-recommendation migrations, but are not enforced when a migration is initiated by a user.
There are two type of anti-affinity rules:
- Inter-VM Anti-Affinity Rules : Controls which virtual machines should never be kept on the same datastore
- Intra-VM Anti-Affinity Rules: Controls which virtual disks associated with a particular virtual machine must be kept on different datastores
Creating Inter-VM Anti-Affinity Rules:
To create inter-VM anti-Affinity rule Click on the Datastore cluster>> Manage >> Settings >> Rules >> add , name the rule choose the VM anti-Affinity and select at least 2 VM’s .
Creating Intra-VM Anti-Affinity Rules:
To create intra-VM anti-Affinity rule Click on the Datastore cluster>> Manage >> Settings >> Rules >> add , name the rule choose the VMDK anti-Affinity and select at least 2 HDD’s .
Override VMDK Affinity Rules:
You might tried to configure VMDK Affinity Rules and the operation is failed , the reason is VMDK affinity rules are enabled by default for all virtual machines that are in a datastore cluster. You can override the default setting for the datastore cluster or for individual virtual machines.
from the same menu , click on VM Overrides >> Add >> + >> change “keep VMDK together” option to NO , then you can apply the rule
Thanks for reading