In my recent gallery, which explains how to provision a VMware ESXi server to an IPv6 storage target, I was surprised that many software-based storage systems don’t support IPv6 currently. While I believe we are quite far from mainstream adoption of IPv6 for private, internal storage networks, it may be the right time to get familiar with the configuration in a lab capacity. In the gallery I used a software-based storage product that would provide a single iSCSI target. That was the approach with the gallery, as I used ESXi and connected the iSCSI initiator to the target over IPv6 in a testing-only capacity. To level-set, a software-based storage device would be something that can be run on any piece of hardware; frequently on a dedicated server with a lot of drives or a virtual machine for testing purposes.
What I discovered is that just because the operating system supports IPv6; that doesn’t mean that the storage software does also. Specifically, if the storage software can run on a Windows-based server (which does support IPv6); the iSCSI (or NFS) configuration may not support IPv6. Here are a few of the software-based storage products that do support IPv6 for iSCSI traffic:
Windows Server 2008 R2 Storage Server: The Windows iSCSI target is very simple to configure; simply selecting a global setting on which IP address (IPv4 or IPv6) that the iSCSI configuration is to run on. This is shown in Figure A below:
FreeNAS: This popular free storage product can provide a number of storage features, including an iSCSI target, file server, print server, and other popular storage-related protocols. IPv6 support within FreeNAS is shown in Figure B below:
What is clear is that we are not entirely ready for IPv6. I believe that external-facing IP addressing will obviously have to go first to IPv6, followed by clients and servers internally. Storage protocols such as iSCSI may be the last to move to IPv6; but it is important to know the ropes of this new configuration before the time comes. I don’t think it will make sense in a few years to “hold out” on IPv4 for special segments such as storage networking; as then the question would be why storage networks are different as every other network that we will soon support.
This discussion may be ahead of its time; but the debate lives on as to whether we should embrace IPv6 for storage networks. What is your stance on protocols such as iSCSI in regards to IPv6? Share your comments below.