RAM disk vs large Squeezelite buffer?

[koko6969koki]

Thank you!

Today I was playing with Snakeoil a little bit more.
Since I have a couple of Squeezeboxes, an original Slimdevices V3 and a Touch, I have concentrated on LMS first, since I wanted to make a multiroom system with my NUC running Snakeoil + LMS.

But after I started exploring MPD, I have discovered that I like it's sound even better!
Snakeoil with MPD sounds really impressive! You have done a great job!
It is much closer to my MacMini running Audirvana+, in some aspects even better, so it seems that MPD will be my player of choice for "serious" listening.

So, naturally,  I wanted to do the similar RAM buffer thing that I have achieved with LMS and Squeezelite.

Here https://www.musicpd.org/doc/html/user.html I see that there is a similar setting for MPD called Input Cache:
 
Configuring the Input CacheThe input cache prefetches queued song files before they are going to be played. This has several advantages:

• risk of buffer underruns during playback is reduced because this decouples playback from disk (or network) I/O
  
• bulk transfers may be faster and more energy efficient than loading small chunks on-the-fly
  
• by prefetching several songs at a time, the hard disk can spin down for longer periods of time
  

This comes at a cost:

• memory usage
  
• bulk transfers may reduce the performance of other applications which also want to access the disk (if the kernel’s I/O scheduler isn’t doing its job properly)
  

To enable the input cache, add an input_cache block to the configuration file:
input_cache {
size "1 GB"
}
This allocates a cache of 1 GB. If the cache grows larger than that, older files will be evicted.

 
The only problem is that I don't know how to apply this setting.

I have tried to locate the mpd.conf file, and the only one I was able to find is /var/www/scratch/mpd.conf
which seemed to be an unusual location according to the MPD literature that I've found online.

Anyway I decided to give it a go, and I tried to edit it with Nano. 
The problem is that edits don't "stick"!
I can open the mpd.conf file, add the cache setting and save it,
but when I start MPD playback, the edit that i have done just disappears from the configuration file. 
The same thing happens when I reboot the machine.

How can I make edits to mpd.conf permanent?
And, maybe the better question is am I editing the right file?!
Or, is there some other way to apply this input cache setting to MPD?
Out of despair  I have even tried the player setting field in Snakeoil web interface that worked for Squeezelite, but no luck!