How do I know if my drive is a bottleneck?

I have been on a performance monitoring expedition. I constantly watch Resource Monitor now and notice that my Disk activity, never really goes much above 10MB/sec.

I have a Samsung PRO 850, which has a SATA capability of 6GB/sec. I have noticed the new Samsung PRO 960 drives don't have the same SATA interface and instead have a new NVMe interface and supposedly is the reasons it is Hugely faster than the 850*.

My question, is would this new interface actually help my regular disk activity?

How do i tell if my drive is being bottle necked?

I don't actually have NVMe capability on my current hardware, if I determined my disk was bottle necked, Would adding another SSD and selectively moving high impact files to the second SSD help?

http://ssd.userbenchmark.com/Compare/Samsung-960-Pro-NVMe-PCIe-M2-512GB-vs-Samsung-850-Pro-256GB/m182182vs2385

Devin Gleason Lambert

Posted 2017-04-19T12:09:49.327

Reputation: 151

Answers

Have a look in the performance Monitor (perfmon) for the 'Avg. Disk Queue Length' on that disk.

If it's anything above 0.0 (1.0 etc), then the system is waiting for the disk, and your disk is the bottleneck. If the wait stays below 0.1. (say 0.001) then the disk isn't being slow.

Stese

Posted 2017-04-19T12:09:49.327

Reputation: 1 037

This is awesome, but can you please provide more detail on how to setup the monitor before I accept your answer? Possibly provide some screen shots too? – Devin Gleason Lambert – 2017-04-19T12:46:26.460

1I found the setting on the default screen, in the performance tab. I don't know much more about that specific tool, sorry. :) I'll add a screenshow showing this. – Stese – 2017-04-19T12:49:09.553

The 10MB/s read is probably when you don't do much.

If you want to practically test, get HDTune and do a disk benchmark or make a big file archive (~8GB should do) and copy it as a test.

As for the interface, 950 Pro is comparable to the SM951 AHCI (which in turn is actually a little above SM951 NVMe). The 850 Pro offers about half the performance of the 950 Pro, so it's a matter of SSD design/generation, not interface.

Numbers here.

Overmind

Posted 2017-04-19T12:09:49.327

Reputation: 8 562

I would also recommend to try Diskspd. We usually make use of it in order to get relevant performance numbers from the storage subsystem. It can do stress testing, simulating workload and it provides flexible settings for users. – batistuta09 – 2017-04-24T11:30:12.227

That's useful for small servers. – Overmind – 2017-04-24T11:51:32.460