As part of my storage vendors to check out at VMworld 2013 in San Francisco, one of the vendors I really wanted to catch up with was SanDisk and to learn more about their FlashSoft product. FlashSoft are run as the software division of SanDisk. In August 2012, they released version 3.0 of their I/O acceleration software, compatible with vSphere 5.0. In April 2013, they released version 3.1 which works with vSphere 5.0 & 5.1. I caught up with a number of folks from the FlashSoft team at VMworld 2013 to learn more about their product, and what their plans were going forward.
I will start with a caveat. The plan is to support both Solid State Disks and PCIe flash devices on VSAN. However, for the purposes of this post, I will refer to this flash resource as an SSD for simplicity.
SSDs serve two purposes in VSAN. They act as both a read cache and a write buffer. This dramatically improves the performance of virtual machines running on the vsanDatastore. In some respects VSAN can be compared to a number of ‘hybrid’ storage solutions in the market, which also use a combination of SSD & HDD to boost the performance of the I/O, but which have the ability to scale out capacity based on low-cost HDD. Read on to learn more about read cache and write buffering on VSAN.
This post contains the list of items you will need to get started with VSAN. I’ll also try to highlight some best practices when it comes to configuring VSAN. First off, lets start with the software requirements – those are the easy bits. You will need ESXi version 5.5 and vCenter server version 5.5. The vCenter server can be either the Windows version or the appliance version; both support VSAN. Finally you will need to familiarize yourself with the vSphere web client if you haven’t already done so. VSAN can only be managed from the vSphere web client; it is not supported in the older C# client.
Last year, NetApp announced a new host side cache accelerator feature to compliment their Virtual Storage Tiering (VST) technology. Rather than keeping all your data in flash, VST places hot data in flash while moving cold data to cheaper and slower media. NetApp are offering this as an end-to-end technology, from server to array controller (Flash Cache) to disk pools (Flash Pools). One of the major parts of this is Flash Accel, which was also announced in the latter part of last year, and is the server-side flash component of VST. On the back of their recently announced All Flash Array, NetApp are also making Flash Accel available to the general public.