A Quick Intro to SPEC SFS 2014

The Standard Performance Evaluation Corporation (SPEC) are in the process of transitioning the "Solution File Server" standard from SPECsfs2008 to SPECsfs2014. I thought I would take this opportunity to provide a bit of an overview for those interested in NAS storage performance.

While SPECsfs2008 has been useful, it is now a bit of a blunt tool as it is only reflective of a single workload. The majority of operations were GETATTR & LOOKUP accounting for 50% of operations just for those two items while reading and writing activity was only 28%, the full list is below.

Another problem with the standard is that the maximum logical transfer size was limited to 256KB. This was fine in 2008 but in 2015 working in logical chunks of 1MB or higher is not only technically possible but rapidly becoming common place.

Some decent thought has been put into the new standard and it now consists of a variety of workloads. This helps it comparing storage for your particular workload or at least something similar to it. The four workloads are as follows:

• VDA - Video Data Acquisition (Streaming)
• VDI - Virtual Desktop Infrastructure
• SWBUILD - Software Build
• DATABASE - Database Workload

Each workload has it's own characteristics which are documented in detail.

While none of these exactly characterise a VFX workload (not that there is any such thing as a standard VFX workload) the VDA component does stress a system in ways of writing full files at larger IO transfer sizes (VDA1) and reading back multiple streams at a time that again are of a decent IO transfer size (VDA2). The stream corresponds to a roughly 36Mb/s bit rate which by SPEC is considered in the upper range of high definition video.

I like this test as it is a nice mix of IOPS and throughput. Read IO transfer size is a range of 64K to 1MB with a slight weighting to 512K. It also deals in streams of a decent size (24GB for the VDA component).

On it's own VDA (1&2) will be useful for evaluating storage for general VFX workload characteristics, but as there is such variety in the VFX world looking at the other three workloads in context with the VDA workload will determine how well the storage can cope when not just perfect streaming conditions.

The only problem with SPECsfs2014 today is that their haven't been any vendors release results yet! There is one set of results up which is simply a reference solution so people can get an understanding of what the output should look like.

SPECsfs2008 is now being retired with final results being accepted for review only until April 27, 2015 with the review cycle ending on May 12, 2015. After that all new submissions will need to be SPECsfs2014, but vendors can submit their results for SPECsfs2014 now.

I look forward to seeing results from all the key players as it will give customers much more guidance on the performance capability of competitive systems.

NFS Version 3 Operation

SPECsfs2008

LOOKUP

24%

READ

18%

WRITE

10%

GETATTR

26%

READLINK

1%

READDIR

1%

CREATE

1%

REMOVE

1%

FSSTAT

1%

SETATTR

4%

READDIRPLUS

2%

ACCESS

11%

COMMIT

NA