How to extend VMFS datastore connected to NetApp iSCSI storage array https://inode-2-blocks.blogspot.com

1. How to Grow VMFS Datastore connected to NetApp
Storage Array via Software iSCSI
Simple two-step process:
1. FILER SIDE: Increase Volume and LUN Size using NetApp Oncommand System Manager
2. HOST SIDE: Increase VMFS Datastore Size using VMware vSphere client
Lab setup: ESXi 5.5 environment with NetApp ONTAP simulator 8.2.1 connected via iSCSI
ashwinwriter@gmail.com
July, 2014

2. Some information to start with
Types of Physical Storage
The ESXi storage management process starts with storage space that your storage
administrator preallocates on different storage systems.
ESXi supports the following types of storage:
 Local Storage -> Stores virtual machine files on internal or directly connected
external storage disks.
 Networked Storage -> Stores virtual machine files on external storage disks or arrays
attached to your host through a direct connection or through a high-speed network.
Networked Storage: [FC/iSCSI: Block protocol based]
Networked storage consists of external storage systems that your ESXi host uses to store
virtual machine files remotely. Typically, the host accesses these systems over a high-speed
storage network.
Networked storage devices are shared. Datastores on networked storage devices can be
accessed by multiple hosts concurrently. ESXi supports the following networked storage
technologies.
 Fibre Channel (FC)
 Internet SCSI (iSCSI)
Note: Accessing the same storage through different transport protocols, such as iSCSI and
Fibre Channel, at the same time is not supported
Fibre Channel (FC):
Stores virtual machine files remotely on an FC storage area network (SAN). FC SAN is a
specialized high-speed network that connects your hosts to high-performance storage devices.
The network uses Fibre Channel protocol to transport SCSI traffic from virtual machines to the
FC SAN devices.
To connect to the FC SAN, your host should be equipped with Fibre Channel host bus adapters
(HBAs). Unless you use Fibre Channel direct connect storage, you need Fibre Channel switches
to route storage traffic. If your host contains FCoE (Fibre Channel over Ethernet) adapters,
you can connect to your shared Fibre Channel devices by using an Ethernet network.

3. Following figure depicts virtual machines using Fibre Channel storage:
Internet SCSI (iSCSI):
Stores virtual machine files on remote iSCSI storage devices. iSCSI packages SCSI storage
traffic into the TCP/IP protocol so that it can travel through standard TCP/IP networks
instead of the specialized FC network. With an iSCSI connection, your host serves as the
initiator that communicates with a target, located in remote iSCSI storage systems.
ESXi offers the following types of iSCSI connections:
 Hardware iSCSI: Your host connects to storage through a third-party adapter capable
of offloading the iSCSI and network processing. Hardware adapters can be dependent
and independent.
 Software iSCSI: Your host uses a software-based iSCSI initiator in the VMkernel to
connect to storage. With this type of iSCSI connection, your host needs only a
standard network adapter for network connectivity.
Note: You must configure iSCSI initiators for the host to access and display iSCSI
storage devices

4. Following figure depicts virtual machines using different types of iSCSI initiators:
 In the left example: Host uses the hardware iSCSI adapter to connect to the
iSCSI storage system.
 In the right example: Host uses a software iSCSI adapter and an Ethernet NIC
to connect to the iSCSI storage.
Networked Storage: [NAS/NFS: File-based protocol]
ESXi can access a designated NFS volume located on a NAS server, mount the volume, and use
it for its storage needs. You can use NFS volumes to store and boot virtual machines in the
same way that you use VMFS datastores.
ESXi supports the following shared storage capabilities on NFS volumes:
 vMotion
 VMware DRS and VMware HA
 ISO images, which are presented as CD-ROMs to virtual machines
 Virtual machine snapshots
When you work with NFS storage, the following considerations apply:
 The maximum size of NFS datastores depends on the support that an NFS server
provides. ESXi does not impose any limits on the NFS datastore size.
 If you use non-ASCII characters to name datastores and virtual machines, make sure
that the underlying NFS server offers internationalization support. If the server does
not support international characters, use only ASCII characters, otherwise
unpredictable failures might occur.

5. How Virtual Machines Access Storage
When a virtual machine communicates with its virtual disk stored on a datastore, it issues
SCSI commands. Because datastores can exist on various types of physical storage, these
commands are encapsulated into other forms, depending on the protocol that the ESXi host
uses to connect to a storage device.
ESXi supports:
 Fibre Channel (FC)
 Internet SCSI (iSCSI)
 Fibre Channel over Ethernet (FCoE)
 NFS protocols.
Regardless of the type of storage device your host uses, the virtual disk always appears to the
virtual machine as a mounted SCSI device. The virtual disk hides a physical storage layer from
the virtual machines operating system. This allows you to run operating systems that are not
certified for specific storage equipment, such as SAN, inside the virtual machine.
The following graphic depicts five virtual machines using different types of storage to
illustrate the differences between each type.

6. Following table compares the ESXi different types of storage support
NetApp Storage Systems iSCSI recommendation
1. If any of your iSCSI initiators are a part of an initiator group (igroup), disable ALUA on
the NetApp filer.
2. Set LUN type and initiator group type as:
 LUN type – VMware (if VMware type is not available, use Linux).
 Initiator group type – VMware (if VMware type is not available, use Linux)
Courtesy:
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-
server-501-storage-guide.pdf

7. Steps to grow VMFS datastore on the NetApp Array
1. FILER SIDE: Increase Volume and LUN Size using NetApp Oncommand System Manager
2. HOST SIDE: Increase VMFS Datastore Size using VMware vSphere client
FILER SIDE PROCESS:
Please note – Volume & LUN resizing is 100% Non-disruptive, Quick & Safe process on NetApp
Filer.
1. VOLUME: After making sure that the Aggregate has enough space to
accommodate volume resize, open NetApp Oncommand system manager |
select the volume and click resize.
2. This will start the “Volume Resize Wizard”, it is self-explanatory | Enter
the new size | you will be asked whether you want to keep the snaps or
not. In most situations, snapshots clean-up are done automatically
according to retention schedule, therefore just click Next.
3. Review the changes and click 'Next' to resize the volume | click 'Finish' to
close the wizard.
4. LUN: Now it‟s time to extend the LUN inside the VOLUME which we just
extended in previous step. Select the LUN and click EDIT as shown in
figure below.
My thoughts: It would be more helpful had NetApp provided „resize‟ button for LUN
as well, instead of „EDIT‟, for some reason it just doesn‟t sound right.
To resize LUN, just click ‘EDIT’…

8. 5. Enter the „new size‟ and click save & close, as simple as that.
Note: When you click „save‟ & „close‟ you will be presented with a message box –
Indicating: storage side stuff is done and now do the expansion on the host side as
seen in the figure below.

9. HOST SIDE PROCESS:
1. Log into vCenter server or ESXi host | Select the ESXi host | click „Storage
Adapters‟ | click „Configuration‟ | Click „Refresh‟.
Note: You can also click „Rescan‟ but a refresh should do the job, in my case it worked.
2. Now, Go to ‘Storage’ tab | configuration | select the datastore which we want to
resize and click „Properties‟.

10. 3. Once the properties window opens, click „Increase‟ to resize VMFS volume, as
shown in the figure below.
Clicking 'Increase' pops-up the wizard | select the device on which the datastore resides and
click 'Next'. [You may have to click refresh few times before the newly carved device shows
up]
Note: In my 'Lab setup', it was fairly simple as I had only one LUN carved out, but in the real
production environments there could be many devices listed there and hence make sure you
select the correct device, b'cos if you selected another device accidently, it will add an
extent to the existing VMFS volume using another LUN, which is probably not what you want
to achieve.

11. For example:
If you want to extend the VMFS datastore residing on the same device [LUN] then select the
LUN you resized on the Storage Array and go ahead with the rest of the steps. Basically, we
are extending an extent on the same device, instead of adding a NEW EXTENT [another LUN].
Whereas, if you wanted to add a NEW EXTENT [another device / LUN] you can select another
device and click NEXT as shown in figure below.

12. In the example below, I can also choose to add another LUN of size 4GB as „Extent‟ to the
existing 56GB VMFS volume.
4. In the next screen – Carefully review the changes and click „Next‟.

13. 5. In the next screen, choose how much of the newly added space will be used and
click Next.
6. Finally, review all the changes and click „FINISH‟.
If all goes well – Datastore [VMFS Volume] would be grown as expected and then you should
be able to either create more VMs on it or move VMs to this Datastore.
ashwinwriter@gmail.com
July, 2014