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in blueprint - 22 May, 2016
by mordi - no comments
VCAP-DCV Deploy Objective 2.1 – part 4

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:

  • Deploy and configure VMware Virtual SAN
  • Upgrade VMware storage infrastructure
  • Configure / View VMFS locking mechanisms
    • ATS-Only mechanism
    • ATS_SCSI mechanism
  • Configure Storage I/O Control to allow I/O prioritization

Lab Setup:(not including vSAN)

Using VMware workstation:

  • Microsoft Servers 2012R2 for Services (DNS , DHCP, etc…)
  • installed esx0
  • Installed VCSA
  • Storage device that can support iSCSI ( i am using Netgear ReadyNAS 202)

 Documents used:

  • vSphere6 Storage Guide

Deploy and configure VMware Virtual SAN:

Please check my previous post on vSAN:

VCP6-DCV blueprint section 3:Configure and Administer Advanced vSphere 6.x Storage -Objective 3.2 – Part 1

and

VCP6-DCV blueprint section 3:Configure and Administer Advanced vSphere 6.x Storage -Objective 3.2 – Part 2

 

Upgrade VMware storage infrastructure:

In this objective  we will cover the following topics:

  • Upgrading VMFS datastores
  • Increasing VMFS datastore  capacity

Upgrading VMFS datastores:

Since VMFS3 and VMFS5 have different characteristics you will have to take that into consideration when upgrading the filesystem.

here are some of the differences taking from the VMware storage guide.

VMFS5_2

Source: VMware vSphere Storage document

 

VMFS5_1

Source: VMware vSphere Storage document

In my lab i dont have VMFS3 or older but to do the upgrade just right click on the datastore and click on upgrade to VMFS5

VMFS5_3

Increasing VMFS datastore  capacity :

Expand:

  • Right click and increase the size of the datastore
  • choose my partition configuration
  • Re-Scan again on all ESXi hosts and verify datastore size

here are the screenshots:

VMFS5_4VMFS5_5VMFS5_6VMFS5_7

Extend:

You will need to add additional LUN to aggregate the space  and after scanning i can increase the datastore again and verify!

VMFS5_8VMFS5_9VMFS5_10VMFS5_11

 

Configure / View VMFS locking mechanisms

Since VMFS is used in a shares storage and multiple host can access the same datastore , we need some sort of locking mechanisms

VMware offer two mechanism:

  • ATS-Only Mechanism:
  • ATS+SCSI Mechanism

From VMware storage document

” ATS-Only Mechanism: The ATS algorithm supports discrete locking per disk sector. All newly formatted VMFS5 datastores use the ATS-only mechanism if the underlying storage supports it, and never use SCSI reservations. When you create a multi-extent datastore where ATS is used, vCenter Server filters out non-ATS devices. This filtering allows you to use only those devices that support the ATS primitive.

ATS+SCSI Mechanism: A VMFS datastore that supports the ATS+SCSI mechanism is configured to use ATS and attempts to use it
when possible. If ATS fails, the VMFS datastore reverts to SCSI reservations. In contrast with the ATS locking, the SCSI reservations lock an entire storage device while an operation that requires metadata protection is performed. After the operation completes, VMFS releases the reservation and other operations can continue. ”

Display VMFS Locking Information:

Run the following command to view the locking modes for the datastore : esxcli storage vmfs lockmode list 

locking1

 

Upgrade to ATS-Only:

Prerequisites:

  • Latest version of vSphere
  • from the command above make sure that in the ATS compatible is TRUE
  • In Online upgrade mode verify that all hosts have consistent storage connectivity to the VMFS datastore.
  • in Offline upgrade mode Verify that no hosts are actively using the datastore.

Online upgrade:

If you plan to complete the upgrade of the locking mechanism by putting the datastore into maintenance mode, disable Storage DRS.

  • Run the following command to perform the upgrade: esxcli storage vmfs lockmode set -a|–ats -l|–volume-label= VMFS label -u|–volume-uuid=VMFS UUID.
  • Unmount and mount the datastore.
  • Put the datastore into maintenance mode and exit maintenance mode

Offline upgrade:

  • Run the following command to perform the upgrade: esxcli storage vmfs lockmode set -a|–ats -l|–volume-label= VMFS label -u|–volume-uuid=VMFS UUID.

Downgrade to ATS+SCSI:

Same procedure as above for online/offline and run the command : esxcli storage vmfs lockmode set -s|–scsi -l|–volume-label= VMFS label -u|–volume-uuid=VMFS UUID.

 

Configure Storage I/O Control to allow I/O prioritization:

Storage I/O control its like QOS for your datastore , you can control the amount of I/O per VM during period of I/O congestion.When you enable SIOC the ESXi host start to monitor the latency and when a latency threshold reached SIOC allocate resource in proportion of their shares.

Enable and configure SIOC:

by default SIOC is disabled to enable SIOC on a datastore: Click on the datastore >> Manage>>Setting >> General >> Edit

You can configure % peak throughput  or adjusted to manual when you can actually control the latency.

SIOC1

Once SIOC is enable you will be able to configure the Shares and I/O limits for a specific VM,

SIOC2

To monitor SIOC resource allocation (Shares and Limits) go to Datastore >> Related Objects>> Virtual Machines.

SIOC3

 

Thanks for reading

Mordi.

 

 

 

 

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