Music Servers/External Drives

Roon makes it very easy to share a variety of locally networked storage devices and make them integrate seamlessly with streaming services (Tidal/Qobuz).

I host my local music library on a headless Mac Mini, my "Jukebox", which I access via Screen Sharing from a MacBook Pro.  Roon continuously monitors a folder on the Mac for updates. I store ripped CDs on the Mac, as well as music files purchased from HD Tracks, Qobuz, or other vendors.  Roon Core runs on a separate, dedicated music server (a sonicTransporter i9), although it also can run on the Mini.  Both the sonicTransporter and the Mini can run certain DSP applications such as HQ Player.

Some audiophiles dislike having a full-function computer in a HiFi system, especially one co-located with the main HiFi components.  I find it very useful and versatile. I don't notice any fan noise. Occasionally a DSP application fails to launch until I respond to a system event (such as an automatic software upgrade process).  Those interrupts can be minimized by turning off (or carefully scheduling) processes such as Time Machine backups.

I also have an SSD inside the sonicTransporter.  Lately I only use it to store a backup copy of music files, and have it disabled in Roon's storage settings.  At any rate, whether you're using a full-function computer, a NAS, an individual USB-attached SSD, etc.,, it does not need to be a device specifically made for audio files.  However, the Bluesound Vault is such a device, which you might want to check out if only to research what's possible.  

I recommend using Exact Audio Copy for ripping CDs.  It provides a bit perfect rip and is free shareware.  I don't think that you can rip to ALAC, but conversion between ALAC, FLAC, WAV and many other lossy and lossless formats is easy with DBPowerAmp, which is my favorite conversion software.

I use a Seagate 5 terrabyte hard drive attached to Cambridge Audio N851 Azur for most of my listening and it sounds great.  It provides the flexibility to play all sorts of formats and high resolution files.  I do highly recommend using a good USB connection between the HD and your server/streamer.  I was skeptical, but adding an Audioquest Diamond USB 3.0 cable and an Audioquest Jitterbug between the Seagate and the 851N made the most dramatic difference in sound than any other cable improvement I have made.  The sound immediately became fuller, more present and nuanced in my system.  Good luck!   

Thank you all for your replies and detailed explanations. This is very useful information. 
SW

SSD with max. data transfer rates over 800 mbps.  This will work much better than 7200 rpm HDD with only 160 mbps in terms of indexing on the first setup or later update.  No moving parts inside SSD makes it less volunerable and hence longer life expectency.  After all, losing data after a long time collection is excruciating.  In addition, SSD reads data without generating vibration and is supposed to give less electric noise that compromises SQ.

Lanx0003 makes a good point.  If you use an external hard drive, BACK IT UP REGULARLY!!!  They have a tendency to fail with little or no notice.  I keep a clone of my main drive connected to a difference stereo in the house.  I find that the Seagates are the most reliable, but don't risk a catastrophic loss of a curated collection for failing to spend an additional $150 or so on a second hard drive.