Windows Server 2012 File Server Tip: New per-share SMB client performance counters provide great insight

Windows Server 2012 and Windows 8 include a new set of performance counters that can greatly help understand the performance of the SMB file protocol. These include new counters on both the server side and the client side.

In this post, I wanted to call your attention to the new client-side counters that show the traffic going to a specific file share. In the example below, we see the performance counters on a computer called FST2-HV1, which is accessing some files on the VMS1 share on a file server cluster called FST2-FS. This is actually a Hyper-V over SMB scenario, where a VM is storing its VHDX file on a remote file share. I started a light copy inside the VM to generate some activity.

 

 

This simple set of counters offers a lot of information. If you know how to interpret it, you can get information on IOPS (data requests per second), throughput (data bytes per second), latency (average seconds per request), IO size (average bytes per request) and outstanding IOs (data queue length) . You can also get all this information for read and write operations.  There’s a lot you can tell from these data points. You can see we’re doing about 910 IOPS and we’re doing more writes than reads (648 write IOPS vs. 262 read IOPS). However, we’re doing larger reads than writes (in average, 104KB reads vs. 64KB writes). Reads are faster than writes (5 milliseconds vs. 8 milliseconds). In case you’re wondering, the workload running here was a simple copy of lots of fairly large files from one folder to another inside the VM.

If you’re familiar with the regular disk counters in Windows, you might notice a certain resemblance. That’s not by accident. The SMB client shares performance counters were designed to exactly match the disk counters. This way you can easily reuse any guidance on application disk performance tuning you currently have . Here’s a little table comparing the two sets:

Type	Disk Object Counter	SMB Client Shares Counter
IOPS	Disk transfers / sec	Data Requests/sec
	Disk reads / sec	Read Requests/sec
	Disk writes / sec	Write Requests/sec
Latency	Avg disk sec / transfer	Avg. sec/Data Request
	Avg disk sec / read	Avg. sec/Read
	Avg disk sec / write	Avg. sec/Write
IO Size	Avg disk bytes / transfer	Avg. Bytes/Data Request
	Avg disk bytes / read	Avg. Bytes/Read
	Avg disk bytes / write	Avg. Bytes/Write
Throughput	Disk bytes / sec	Data Bytes/sec
	Disk read bytes / sec	Read Bytes/sec
	Disk write bytes / sec	Write Bytes/sec
Queue Length	Avg. Disk Read Queue Length	Avg. Read Queue Length
	Avg. Disk Write Queue Length	Avg. Write Queue Length
	Avg Disk Queue Length	Avg. Data Queue Length

I would encourage you to understand your application storage performance and capture/save some samples after you tune your applications. This way you can build a library of baseline performance counters that you can later use for troubleshooting performance issues.

Comments

• Anonymous
  January 01, 2003
  This is an useful article.
• Anonymous
  November 22, 2012
  Many thanks Jose.. I will print it out and use these to baseline my new Hyper-V hosts.
• Anonymous
  June 05, 2014
  This is the third blog post in a series about Cluster Shared Volumes (CSV). In this post we will go over
• Anonymous
  July 07, 2014
  In this post, I'm providing a reference to the most relevant content related to Windows Server 2012
• Anonymous
  January 21, 2017
  Very informative article. Thanks.
• Anonymous
  July 18, 2017
  The comment has been removed