Eli Singer

SSD IOPS- does it matter?

1 post in this topic

In short- why should we care about IOPS?


In depth- this is what i don't understand:

I've read quite a number of articles and forum posts regarding this issue and couldn't come to a conclusive answer.

Basically, in order to know if the IOPS is a limitation one would need to know how many IOPS are needed by the machine.
I couldn't find any relevant information on that apart from Database info like this: http://blog.unidesk.com/do-vdi-iops-matter which states 2000 IOPS as a typical workload.

This article states that IOPS in flash (SSD) is practically unlimited and since latency is also not an issue in SSD's, it seems that the only relevant measurement is Throughput.
https://flashdba.com/2013/06/27/storage-myths-iops-matt...
The comments are really interesting too.

This also seem to follow the same lines: https://storageswiss.com/2015/02/23/what-are-iops-and-s...

The thing is, all these articles are from professional storage point of view and they talk about it in the relation with an array of physical disks in a data center and such.
What I'd like to know is weather these figures means anything to mortals?

I mostly do video editing and grading.
I tend to think that the following is an ideal setup for me (drives wise)

1. OS and Programs- 250GB SSD
2. Media cache- 250GB SSD
3 .Media drive for hot projects- 1tb SSD or 2 500GB SSD's in RAID 0
4. Data drives (backups and all other stuff)- FreeNAS server with 6 8TB NAS Drives

Let's concentrate on the SSD's.
On the OS drive and the Media cache drive I'll be doing mostly small reads and writes.
On the Media Drives I'll be doing very large Sequential Reads (Video files).

Currently I have only one SSD which is used for OS, Programs, and media cache. This is on a Intel 520 series 240GB drives which is rated at:
Sequential Read (up to) 550 MB/s
Sequential Write (up to) 520 MB/s
Random Read (8GB Span) (up to) 50000 IOPS
Random Write (8GB Span) (up to) 60000 IOPS

For comparison, the Samsung 850 EVO 250GB specs are this:
Up to 540 MB/s Sequential Read
Up to 520 MB/s Sequential Write 
Up to 97,000 IOPS Random Read
Up to 88,000 IOPS Random Write

I want to add the next SSD on the list which will only serve for media cache. Later on (budget you know) I'll add the large 1tb hot projects media drive.

I'm thinking of getting the Intel 600p Series 256GB M.2 SSD which is rated:
Sequential Read (up to) 1570 MB/s
Sequential Write (up to) 540 MB/s
Random Read (8GB Span) (up to) 71000 IOPS
Random Write (8GB Span) (up to) 112000 IOPS

Regarding all the information above, will it be better suited for the OS, for the Media Cache, or for Media drive?

And could somebody please explain why everybody is talking about IOPS? How is that important? How is that a limitation in this kind of setup?
Is there an application that needs 50,000 IOPS?? What is a normal IOPS rate?

This also begs the question, why should we consider "Pro" drives like the Samsung 850 Pro or the Sandisk Extreme Pro when their throughput is essentially the same?
Besides reliability, what's to gain from this drives in terms of performance?

Sorry for the long post...

Eli

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