If some of your VMs have a high load while others are underperforming because the storage is not able to deliver enough, SIOC is the element that can control that. Example of share settings by default on the per vm level. Raw device mappings RDM are not currently supported.
Some arrays might be using automated storage tiering, so in this case you should check the VMware storage compatibility guide and make sure it is compatible with SIOC. Connect to your vCenter Server via the vSphere client and then browse to the datastore icon in the vSphere Client.
Adjust the percentage of peak thresholds if you like. There is also the option to enter another number, but you'll get a nice warning message saying that "Setting improper congestion threshold values could be detrimental to the performance of the virtual machines on the datastore".
The manual value is not in percent but in milliseconds ms. When you click it, you'll see that you can choose from three different predefined values as well.
Click OK to validate and you're done. Proceed with all the shared datastores you might have in your organization or only the ones where you have your business-critical workloads running.
Each time you add a new host that is connected to a shared datastore, you have to re-enable SIOC. Make sure that you're using the correct values and that those values have not been modified. You should enter 30 ms, which is the recommended value. Then view the shares and shares value columns there. Check VMs and their shares value at the cluster level. If you're not using resource pools, you can set shares at the VM level for your critical business VMs.
Controlling and avoiding latency problems at the VM level with SIOC, which is only triggered when contention occurs, is a good way to protect the business-critical workloads you might have in your enterprise. Subscribe to 4sysops newsletter! You should consult SAN's manufacturer manual for recommended values. Setting values too low or too high might not deliver the expected results.
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You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Hope it helps others as well. Click Properties. Click Close. So keeping track of it through vCenter for example to coordinate all hosts is not necessary. Think of it like throttling the port in a virtual distributed switch. To further clarify that last paragraph. A change on the vds, while controlled through vCenter, is universal on all hosts in the vds so the change only needs to happen in one location but each host will react as it needs to.
Even better would be a plugin from the SAN vendors that could automatically manage these groups based on which datastores are sharing the same disks. I will ask the developer though. Especially in larger environments I do see a valid reason to enable this, or even better in any environment where you have multiple VMs on a single datastore which is shared across multiple host you can and will benefit from SIOC at some point.
Duncan: I think the feature has some good uses as it is, I just think that they are limited by the current implementation. It could even be a bad thing in the wrong environment. I think it would be of great value in vCD environment where there is no way to manage the shares on individual VMs and the VM creation would be dynamic.
Where does datastore-wide disk scheduler runs from? Is it Enterprise Plus only? NFS has so many awesome features, but in some ways still feels like the redheaded stepchild of vmware supported storage. The storage layer SLA requirements of the environment and the physical storage array capabilities will be contributing factors here to how you design the SIOC threshold values. Next is to define shares for the business critical virtual machines. These shares are defined at disk level.
Open virtual machine properties and expand hard disk and locate Shares. You can select from Low,Normal and High or you can set a custom value for shares. There is a datastore performance charts which allow monitoring of:. Select Performance from View drop-down menu and select the time range for which you want to view the charts.
SIOC logging. By default, SIOC logging is disabled. To enable logging:. Click Host Advanced Settings. In the Misc section, select the Misc.
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