NFS Best Practices – Part 4: Sizing Considerations

Welcome to the next installment of NFS Best Practices. In this fourth and final best practice section on NFS, I asked a number of our major NAS storage partners some sizing questions. The questions basically fell into 3 different categories: Do you have a recommended NFS volume size/sweet-spot recommendation? Do you have a volume block size recommendation that should be configured on the array? Do you have a recommended number of VMs per NFS datastore? In fact, the responses from the vendors were all pretty similar. Let’s take a look at what they had to say.

Could not detect setting of sitpua for device Error Not supported.

I recently received a question about the following message appearing in the VMkernel logs of an ESXi host: 2012-12-07T12:15:58.994Z cpu17:420151)ScsiDeviceIO: 6340: Could not detect setting of sitpua for device Error Not supported. So what does that mean? Firstly, it isn’t anything to be greatly concerned about. SITPUA, short for Single Initiator Thin Provisioning Unit Attention, is related to Out Of Space (OOS) conditions on Thin Provisioned LUNs. To ensure that an Out Of Space (OOS) warning is sent to just one host using the affected LUN,¬† the SITPUA bit in the Thin Provisioning Mode Page must be set to…

NFS Best Practices – Part 3: Interoperability Considerations

Welcome to part 3 of the NFS Best Practices series of posts. While part 1 looked at networking and part 2 looked at configuration options, this next post will look at interoperability with vSphere features. We are primarily interested in features which are in some way related to storage, and NFS storage in particular. While many of my regular readers will be well versed in most of these technologies, I’m hoping there will still be some items of interest. Most of the interoperability features are tried and tested with NFS, but I will try to highlight areas that might be…

An Introduction to Flash Technology

As many of you are aware, VMware made a number of announcements at VMworld 2012. There were three technical previews in the storage space. The first of these was on Virtual Volumes (VVols), which is aimed at making storage objects in virtual infrastructures more granular. The second was Virtual SAN (VSAN), previously known as Distributed Storage, a new distributed datastore using local ESXi storage. The final one was Virtual Flash (vFlash). However, rather than diving into vFlash, I thought it might be more useful to take a step back and have a look at flash technologies in general.

Heads Up! VSA & Quad Port NIC Support

There was a recent discussion on the forums around the supportability of quad port NICs when deploying the vSphere Storage Appliance. There is an error thrown by the installer when the ESXi host only has a quad port NIC. The error states that the VSA installer ‘Failed to configure network on host’ because it ‘Could not find 2 NICs on the system’. However there is a workaround to allow VSA to install when the ESXi host(s) only contain a single quad port NIC. This is only available on VSA 5.1.x.

An Introduction to Coraid

Another session that I attended during the UK National VMUG earlier this month was an overview of Coraid Technology from Max Brown, one of Coraid’s System Engineers based in the UK. My first introduction to Coraid was at VMworld 2011 & I did a short overview of their AoE (ATA over Ethernet) solution here. I wanted to get along to this session to see what had changed since then. In a nutshell, Coraid present SAN storage as local storage via AoE. How do they do that? Well, Coraid provide the HBA, the AoE initiator software¬† (which must be installed on…