DAS vs SAN vs NAS

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James Tanner

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DAS vs SAN vs NAS
« on: 3 Feb 2019, 03:13 pm »
Hi Folks,

Doing some experiments - any thoughts on which of the following would provide the best fidelity?

DAS is a block device from a disk which is physically [directly] attached to the host machine.
You must place a filesystem upon it before it can be used.
Technologies to do this include IDE, SCSI, SATA, etc.

SAN is a block device which is delivered over the network.
Like DAS you must still place a filesystem upon it before it can used.
Technologies to do this include FibreChannel, iSCSI, FoE, etc.

NAS is a filesystem delivered over the network.
It is ready to mount and use.
Technologies to do this include NFS, CIFS, AFS, etc.

Pundamilia

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Re: DAS vs SAN vs NAS
« Reply #1 on: 3 Feb 2019, 03:48 pm »
I suspect that if one has a full FibreChannel network, the SAN would offer the fastest response and the cleanest signal and therefore perhaps better audio quality. However, given the associated costs, I think most people who don't have a FibreChannel in their home (99.9% of Bryston users) would be better off spending the money on audio equipment or content. Leaving the other two options.

Krutsch

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Re: DAS vs SAN vs NAS
« Reply #2 on: 3 Feb 2019, 07:16 pm »
NAS, without question, as I describe in this post:

https://www.audiocircle.com/index.php?topic=161895.msg1725809#msg1725809

@Pundamilia ...

Quote
I suspect that if one has a full FibreChannel network, the SAN would offer the fastest response and the cleanest signal...

FC is pretty over-the-top for audio applications  :lol:

If you are suggesting this for optical isolation purposes, my post above discusses this (i.e. there are inexpensive, consumer routers that offer SPFs for optical gigabit ethernet, though it's unnecessary for this application - copper Ethernet is already galvanically isolated).

Pundamilia

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Re: DAS vs SAN vs NAS
« Reply #3 on: 3 Feb 2019, 07:34 pm »
I certainly wasn't advocating running fibre through your house (unless you're running a Data Centre out of your garage!). I was just saying that I think a SAN is overkill.   :lol:

zoom25

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Re: DAS vs SAN vs NAS
« Reply #4 on: 3 Feb 2019, 09:34 pm »
Lumin X1 has both copper and optical fibre ethernet inputs.

(I haven't followed the Uptone EtherRegen developments in the past few months, so don't know if John Swenson's research has been published. Aside from leakage and noise measurements with ethernet, they were looking into jitter and phase noise with ethernet which is asynchronous and non-realtime. Yet they think something might be there.)

Anyways, James, what kind of experiments/setups are you doing?

James Tanner

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Re: DAS vs SAN vs NAS
« Reply #5 on: 3 Feb 2019, 09:49 pm »
Lumin X1 has both copper and optical fibre ethernet inputs.

(I haven't followed the Uptone EtherRegen developments in the past few months, so don't know if John Swenson's research has been published. Aside from leakage and noise measurements with ethernet, they were looking into jitter and phase noise with ethernet which is asynchronous and non-realtime. Yet they think something might be there.)

Anyways, James, what kind of experiments/setups are you doing?

Just doing blind listening test with the same music files on the 3 different setups.

James


zoom25

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Re: DAS vs SAN vs NAS
« Reply #6 on: 3 Feb 2019, 10:48 pm »
Just doing blind listening test with the same music files on the 3 different setups.

James

So pull music files from ethernet via NAS, and a USB attached or internal hard drive/SSD for DAS, and something for SAN? What's the equipment setup like? I'm wondering if your setup or purpose is something different than what I'm imagining. Is this with MPD only or DLNA and Roon as well?

zoom25

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Re: DAS vs SAN vs NAS
« Reply #7 on: 3 Feb 2019, 10:50 pm »
NAS, without question, as I describe in this post:

https://www.audiocircle.com/index.php?topic=161895.msg1725809#msg1725809

@Pundamilia ...

FC is pretty over-the-top for audio applications  :lol:

If you are suggesting this for optical isolation purposes, my post above discusses this (i.e. there are inexpensive, consumer routers that offer SPFs for optical gigabit ethernet, though it's unnecessary for this application - copper Ethernet is already galvanically isolated).

So what sounds best for MPD in your setup, your NAS or those Corsair flash drives?

James Tanner

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Re: DAS vs SAN vs NAS
« Reply #8 on: 3 Feb 2019, 10:53 pm »
So pull music files from ethernet via NAS, and a USB attached or internal hard drive/SSD for DAS, and something for SAN? What's the equipment setup like? I'm wondering if your setup or purpose is something different than what I'm imagining. Is this with MPD only or DLNA and Roon as well?

Using the BDP 3 and the BDA3. Have Roon Server as well

James

zoom25

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Re: DAS vs SAN vs NAS
« Reply #9 on: 4 Feb 2019, 09:04 pm »
Using the BDP 3 and the BDA3. Have Roon Server as well

James

Okay, so just the standard BDA-BDP hookup and see how to get the best sound from a music file via different playback methods / attached devices?

I'd be curious to hear about how many people are the Bryston listening team when developing these products and how many can reliably tell different playback methods apart? Also, among those that can tell them apart, do they all prefer the same method or is it a toss-up? Lastly, the one thing I want to know the most is does any difference in noise/jitter show up on the BDP outputs when using different playback methods or attached devices?

On the BDP, I've tried Roon Ready, DLNA Renderer with Audirvana Plus, MPD, Shairplay. I've done this with router acting as NAS, wifi USB adapter, flash drives, external portable and desktop spinning drives, linear power supplies for the drives and network gear, with or without Jitterbug, WAV and FLAC. They sure as hell don't all sound the same. Surely, it should show up on the measurements?

Anyways, the one playback method that stands out very clearly among the group is using the portable USB WD hard drive plugged into the BDP with MPD use. The few times I take the BDP into the large hall, the difference just stands out so clearly. I haven't found any other transport device or BDP playback method that quite fills the room like the portable hard drive. The image and layering just leaps from the speakers and touches you. The centre stage is more locked and as a result you get smoother vocals rather than having this smeared feeling. There is also this amount of air and ambience that gets lost with other method. I can only conclude that either this portable hard drive is adding something artificial that other methods are not, or the other methods are not as good at retaining the ambiance. All other playback method sound more 2D and flatter in comparison. If I had to convince someone that digital devices can sound different, I'd use the portable HDD as the example against whatever else.

sfraser

Re: DAS vs SAN vs NAS
« Reply #10 on: 6 Feb 2019, 04:24 pm »
The bit rate is extremely low for uncompressed audio delivery , assuming appropriate application buffering is available i would not expect an audible  difference between any of the 3  storage and delivery mechanisms.  The use of TCP ensures error free delivery over a network medium. However WiFi might prove to problematic in some instances.  I would suggest if you can  hear differences between the 3 content/delivery mechanisms, the difference might be at the individual  OS/application level and how it deals with USB VS Network  delivery and resources  etc.

I have been using a NAS for years now, with a rack mount 16 TB freeNAS ZFS  server hosting my audio/video content. I use a Raspberry Pi running Squeezebox Server  software with  CIFS mount to the aforementioned NAS server. I have a variety of squeezebox clients streaming content from the Pi server . Works and sounds  great, and the Pi  seems to be able  to deal with the 78K track library. I would move the Squeezebox Server off the Pi and over to virtual machine instance on the FreeNAS server and consolidate things, but I have yet to be successful with that endeavour.