Officially speaking, Logitech only supports running Squeezebox Server on Netgear ReadyNas units. Specifically these models:
NV, NV+, Duo, Pro and NVX models

Squeezebox forums / Logitech Media Server on ReadyNAS / Troubleshooting

Memory

Apacer PC3200 CL3 PN 75.85387.G00

Kingston KVR400X64SC3A/1G
Patriot 1GB 200-Pin DDR SO-DIMM DDR 333 PEP1G2700SLL(PC 2700)
Wintec PC2700-1G/Micron (#38299682) 2 RANK (16-Chip)
Wintec PC3200-1G/Micron (#38290682) 2 RANK (16-Chip)
Wintec PC3200-1G/Qimonda (#38290681) 2 RANK (16-Chip)
Hynix HYMD512M646CFP8-J (16-Chip)
I-O Data AP-SDD333-1G (16-Chip) MT16VDDF12864H)
Crucial CT12864X335 (16-Chip 1GB) (Microns MT16VDDF12864H)
NETGEAR 1GB SODIMM for NV/NV+ (16-Chip)

HYNIX HYMD564M646CP6-J AA
Kingston DDR PC2700 333MHz KVR333SO/1GR
Kingston KVR333X64SC25/1G 1GB DDR

The Kingston has been removed from the list so don't use it.
Crucial #CT12864X40B, description is CT12864X40B 1GB, 200-pin SODIMM, DDR PC3200 memory module


PC2700 (DDR-333) DDR-SDRAM 
SO-DIMM 1GB DDR PC2700 333MHZ CRUCIAL CT12864X335

PNY Technologies Europe 64A0TNDYA8G17 1GB module seems to be working ok in a Duo

I have to say though that I have not noticed any difference in performance. I was hoping 
for an improvement in speed when managing the Logitech media server via the web 
interface while listening to music on my Touch. There is no noticeable improvement 
even after setting the media server to use more memory. This is with radiator 4.1.8 
and media server 7.7.2

Patriot Memory PSD21G66781S

Firmware

Old versions / ReadyNAS / Nightly

If you are using firmware 7.6x you may want to read this topic.

I had to update to 7.7 beta for it finally to work correct. Of course you can always go back to 7.54 as well.. That also worked for me..

USB Disk

Most Reliable Disk USB Compatibility

NAS

Netgear ReadyNAS NV/Duo
Netgear ReadyNAS NV/Duo v2 (ARM)
Netgear ReadyNAS Pro/Ultra/NVX

ReadyNAS Duo v1    $100
ReadyNAS Duo v2    $130
ReadyNAS Ultra 2   $300
ReadyNAS Ultra 4   $550
ReadyNAS Pro 4     $630

Sparc Line

Duo sparc-based IT3107
NV+ sparc-based IT3107

Ultra Line

Ultra2       1.8 GHz Atom D425 (single core) [Update: Starting May 2011 Ultra2 will ship with 1.5 GHz CPU; performance difference is minimal, if any; price decreased by $100.]
Ultra2 Plus  1.8 GHz Atom D525 (dual core)
Ultra4       1.66 GHz Atom D410 (single core)
Ultra4 Plus  1.66 GHz Atom D510 (dual core)
Ultra6       1.66 GHz Atom D510 (dual core)
Ultra6 Plus  E2160 1.8Ghz CPU (dual core)

Pro Line

First Generation (which will likely be discontinued once current supply has been sold off):
NVX Pioneer Edition   Intel Tolapai SiC @ 1.06 GHz
NVX Business Edition  Intel Tolapai SiC @ 1.06 GHz
Pro Pioneer Edition   E2160 1.8Ghz CPU (dual core)
Pro Business Edition  E2160 1.8Ghz CPU (dual core)

Second Generation:
Pro2  1.8 GHz Atom D525 (dual core)
Pro4  1.66 GHz Atom D510 (dual core)
Pro6  E5300 2.6Ghz CPU (dual core)

Compare ReadyNAS

Mini Desktop

Dell Optiplex GX620

Tests

Version: 7.7.2.r9663
Hardware version: 5

Vantec NexStar 3 (Blue case) WD Caviar Green WD10EZRZ 1TB Advanced Format Drive NTFS

Took a vey long time time to complete scan, disconnects while playing.
Removed non-music files, including album art. Problems scanning.
Not usable

Vantec NexStar 3 (Blue case)      
WD Caviar Green WD10EZRZ 1TB     
Advanced Format Drive     
ext2/ext3

Removed from access control list.
Not connected to the network
working well

Vantec NexStar 3 (Black case) Seagate Barracuda ES.2 750 GB ext2/ext3

Not connected to the network. Quicker to scan, stable running.
Connected to the network. Seems to have more problems...

ReadyNAS Duo Seagate Barracuda 7200.10 SqueezeCenter 7.3.2

Fan is noisy

Unit is very slow

Abort scan - possibly problem file on disk

ReadyNAS Installation

RAIDar for Linux

Latest: June 14, 2012 Version 4.1.9, Release Notes
RAIDiator 4.1.6 [1.00a043]  
256 MB [2.5-3-3-7]

Memory Test

test memory To invoke it, power-down the ReadyNAS and depress the front power button, until you see all disk LEDs blink together for the 5th time. Release at that point. The first disk LED will come on to signify the first of an 8-stage memory test Memory test for duo Everything is spelled out there but the main difference is that you should view the DUO as having only the first two of the four LEDs and so the eight-step test indication is shown using only the first two LEDs. So, when the test starts up the patterns will look like this:

10 00 Step 1
01 00 Step 2
11 00 Step 3
00 10 Step 4
10 10 Step 5
01 10 Step 6
11 10 Step 7
00 01 Step 8

After each test is finished, the proper next step is to pull the power cord from the back of the DUO then reconnect and power back up, either repeating the memory test procedure of waiting for the LEDs to flash five times, or just powering up normally by pressing the power button once. To check this, go to Status > Logs > Download all logs and refer to the mem_info.log.

Fan

Crown AGE06025B12U
6800 rpm
34.8 CFM
46.5 dBA

Silenx 
2000 rpm
18 cfm
3 pin
18 dBA

FD-FAN-60 Fractal Designn Silent Series 60mm (6x6x2.5 cm)
3000 rpm
16.1 CFM
3 pin 
19 dBA

NAS Performance

NETGEAR ProSafe Gigabit 8 Port VPN Firewall FVS318G
Firmware Version: 	3.0.5-24
The 318G doesn't have jumbo frame support.

iozone -I -a -s 16M -r 4 -i 0 -i 1 -i 2

Readynas Duo(chlap) Barracuda ES.2 750GB  3NFS
                                                            random  random
              KB  reclen   write rewrite    read    reread    read   write
           16384       4     188     176     1197     1241    1249     189

Readynas Duo(chlap)  WD10EZRX 1TB  8NFS
                                                            random  random
              KB  reclen   write rewrite    read    reread    read   write
           16384       4    3689    4234     6526     6129    5628    3632

Readynas Duo(pbarp) Barracuda ES.2 750GB  3NFS
                                                            random  random
              KB  reclen   write rewrite    read    reread    read   write
           16384       4     196     182     6711     6496    6716     194



Readynas Ultra(chlap)  WD10EZRX 1TB  8NFS
                                                            random  random
              KB  reclen   write rewrite    read    reread    read   write
           16384       4    1323    1119     1294     1318    1336    1249
           16384       4    1228    1283     1290     1066    1283    1278


Readynas Ultra(pbarp)  WD10EZRX 1TB  8NFS
                                                            random  random
              KB  reclen   write rewrite    read    reread    read   write
           16384       4    8954    9811     9981     7358   11386    9721
           16384       4    8931    9766    10694    11313   10030    9712