In my last two articles, I covered NFS configuration and troubleshooting (see Connecting vSphere to NFS the Easy Way and vSphere NFS Troubleshooting Basics) but before I delve back into more advanced topics, I’d like to take a step back and ensure that all the Tintri blog readers are on the same level when it comes to understanding vSphere storage basics. Many admins are thrown into storage and virtualization and just don’t have time to develop a strong level of basic knowledge, which is very important.
I don’t want to get too rudimentary here, but stick with me while I cover some basic terms that we all need to know:
Thus, vmhba1:1:0 would be HBA1, storage processor 1, and LUN 0.
See VMware KB article 101140, Multipathing Policies for more information.
Besides the terms you must know, there are a few common questions that people ask about when implementing vSphere.
Why do I need shared storage?
Your VMs will be stored in a single place — the shared storage — where all ESXi hosts have access and visibility to them. Since all hosts can access them, these VMs can be vMotion’ed from one host to another with Distributed Resource Scheduler (DRS) or restarted when a host fails with vSphere High Availability (HA). Shared storage is a required component of a vSphere virtual infrastructure where you want to take advantage of advanced features.
Should I use block-based or file-based storage?
Examples of SAN block-based storage are Fibre Channel (FC) and iSCSI. An example of NAS file-based storage is the NFS. All of these options are supported by VMware and work well with advanced features you’ll want in your virtual infrastructure. Honestly, there is no right or wrong answer to the block vs. file question. NAS tends to be a bit easier to manage, but both provide excellent performance and if designed well and configured correctly, either option will work well.
How does the popularity and affordability of SSD change my storage decision?
Solid state disks (SSD) provide reliability and consistent performance as the demand for IO increases. Because of its unique benefits over traditional disk, SSD is the best high-performance storage option (and it has become affordable). VMware vSphere can even now be configured to use internal server SSD as secondary (additional) memory for the server, allowing it to run more VMs.
Unique control with VM-level actions for infrastructure functions including snapshots, replication and QoS make protection and performance certain in production, and accelerate test and development cycles.