HOW TO: Tag and Configure a storage device as a Solid State Disk (SSD) in VMware vSphere 5.0 or 5.1  (ESXi 5.0 or ESXi 5.1)

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Andrew Hancock (VMware vExpert / EE Fellow)
MVE^2, Expert of the Year 2017-2011, Scribe 2016-2012, Author of the Year 2018-6,2013-2012 VMware vExpert 2019-2011 30 years of experience.
In VMware vSphere 5.x (ESXi 5.x) there is a new feature called Host Cache Configuration. This new feature allows the VMware vSphere Administrator to configure the VMware vSphere 5.x (ESXi 5.x) host server to use a cache on a Solid State Disks (SSD) for the virtual machine's swapfile for better performance, because the SSD has much faster latency than a traditional mechanical disk. This is also known in VMware Administrator circles as Swap to Host Cache or Swap to SSD. Once Host Cache Configuration has been enabled, the virtual machines will be swapping to SSD, but this swapfile is not a true swap file, and the entire virtual machine swap file (.vswp)  is not stored on the SSD.

However, not all SSD devices are correctly tagged as SSD. This tutorial shows how to tag a Non-SSD storage device as SSD, if you want to experiment with Host Cache Configuration but do not have a SSD to hand. This is not supported by VMware, tagging a non-SSD as a SSD.

The same procedure can be followed to tag a SSD, correctly, if it's not recognized by the VMware ESXi server.

With the current fall in prices for consumer SSDs, it can give a real performance boost to a VMware ESXi 5.x server which is short on memory. Consumer SSDs e.g. Kingston SSDNow V+200 Drive Model SVP200S37A/60G are generally cheaper than server memory. We recently purchased this model for £29.99 GBP.

The commands we will be using in this Tutorial, are the esxcli commands, these commands can be executed on the ESXi shell, through the vMA or PowerCLI esxcli remote version. In this tutorial I'll be logging into the ESXi server, and executing the commands on the ESXi shell.

1. Connect to the VMware vSphere Hypervisor (ESXi) or VMware vSphere vCenter Server

Using the VMware vSphere Client, Login and Connect to the ESXi server, using IP address or hostname of the ESXi server, using root username and password credentials. If you have a VMware vSphere vCenter server, you could also specify IP address or hostname of the vCenter server.Using the VMware vSphere Client, Login and Connect to the ESXi server

2. Check and record the storage device name to be tagged as a SSD

Check there is a VMFS volume already formatted on the storage device, you want to present to the Host ESXi server, as a SSD and record the device name for later in Step 4.

Select Host > Configuration > Storage
storage device to configure as SSDIn the example above, the local storage device mpx.vmhba1:C0:T0:L0 is a local disk, formatted with the datastore name datastore1 as VMFS5. Record the storage device name mpx.vmhba1:C0:T0:L0.

3. Logon to ESXi console (shell) via PuTTY

Using PuTTY a free telnet and SSH client or another SSH client Login and Connect to the VMware Hypervisor ESXi server, using IP address or hostname of the VMware Hypervisor ESXi server, using root username and password credentials.putty SSH terminal sessionlogged in as root to ssh terminal session

4. Create a new SATP rule

At the console or SSH session type the following commands to create a new SATP rule.
esxcli storage nmp satp rule add --satp VMW_SATP_LOCAL --device mpx.vmhba1:C0:T0:L0 --option=enable_ssd

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using the device name recorded in Step 2 above. The console will return a new line. To check the rule has been created correctly type the following commands
esxcli storage nmp satp rule list | grep enable_ssd

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the following screenshot should be displayed
Confirmation of rule creationconfirming the creation of the rule.

5. Claim storage device

At the console or SSH session type the following commands
esxcli storage core claiming reclaim -d mpx.vmhba1:C0:T0:L0

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using the device name recorded in Step 2 above.

I have seen the following error messages when trying to claim devices, either restart the server or use the "unclaim" device command.
Unable to unclaim path vmhba1:C0:T0:L0 on device mpx.vmhba1:C0:T0:L0. Some paths may be left in an unclaimed state. You will need to claim them manually using the appropriate commands or wait for periyou can unclaim the device by specifying the device name.
esxcli storage core claiming unclaim --type device --device device_name

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6. Reload the claim rules

I usually reload the claim rules and run the rules using the following commands:
esxcli storage core claimrule load
esxcli storage core claimrule run

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7. Confirm device is Tagged as SSD

Use the following command at the console, to check if the device has successfully been tagged as a SSD
esxcli storage core device list --device=mpx.vmhba1:C0:T0:L0

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The following output will be displayed for the device.
local device tagged as SSDCheck the output states "Is SSD: true"
You have successfully configured and tagged a local device as a SSD. If you now repeat Step 2 above, you will see the device now states SSD.
storage device to configure or tagged as SSD
In my next Article, I show you how to configure Host Cache Configuration.

Further reading can be found here in the VMware
vSphere 5 Documentation Center :- Tag Devices as SSD

Thank you for reading my article, please leave valuable feedback. If you liked my VMware article and would like to see more Articles from me, please click the Yes button near the: Was this article helpful? at the bottom of this article just below and to the right of this information. Thank You. Do not forget if you have a question about this article or another VMware, Virtualisation, Windows Server 2012 question, why not post a Question for Me and the other Experts Exchange Experts in the VMware, Virtualisation, Windows 2008 Zones. I look forward to hearing from you. - Andy :- twitter @einsteinagogo
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