LINUX or Windows ?
A1. Whilst the 'expert' will immediately reach for LINUX software (OpenMediaVault, Openfiler, Amahi Home Server, NAS4Free etc.), the 'real world' user will stick to Windows.
Why ? ... well, it's mainly because you DO NOT want to learn about the pitfalls and "Catch 22's" of a totally new operating system at the same time as trying to protect (or recover) your irreplaceable data
If you decide to go for Open Source such as a Turnkey Linux NAS, or OpenFiler or FreeNAS (see Note below) (or the commercial version, NASLite), you should spend a bit of time on Google checking for possible problems.
Obvious requirements are :-
1) Data must be held on NTFS formatted RAID-MIRROR drive set = if your NAS suffers from a motherboard failure, you MUST be able to get access to your data by temporarily 'moving' the drive(s) to another computer (which 9 times out of 10 will be running Windows).
Note: that current (and all future) releases of FreeNAS are 64bit only, require a minimium of 8Gb RAM and at least 8Gb disc space and ONLY formats disks with the OpenZFS filesystem ! When you add this to the focus on 'iSCSI' (a complex 'Corporate Data Center' level disk drive specification that means each drive costs more than the entire rest of the computer) it's obvious that FreeNAS is totally unsuitable for 'home use'. For those who wish to persevere anyway, (as of end 2014) it was still possible to download 9.2.1.9 17 Nov. 2014 (the last 32bit verson). My recomendartion is "don't waste your time" ..
2) Your NAS must support 'wake up on LAN'. A NAS needs to be available 24x7, but if your hard drives never turn off and your system never sleeps, not only will you be wasting a lot of power, you will also shorten the life of the drives. 'Wake up on LAN' means you can safely let the NAS 'go to sleep' without having to manually kick it back into life
3) If you fit a UPS, both the UPS and NAS must support 'shut down on Warning of power loss' (i.e the UPS must issue the warning and the NAS must act on it)
A2. If you do go for a non-windows solution, and intend to interface the Server to your home cinema / TV / VR, the Operating System chosen either needs it's own UPnP app. or needs to run Java v6 (so that a Java based DLNA UPnP driver, such as Serviio, can be supported).
Which version of Windows ?
There was a time when those with bottomless pockets could 'invest' $350+ for Microsoft Windows Home Server 2011 (which is based on XP Server 2003). However it seems this is now only available 'embedded' in NAS hardware from OEM's - of course paying through the nose for an 'off the shelf' NAS box also solves the problem of deciding what hardware to use, so those with any Apple product should look no further.
The rest of us will have to 'compromise' with something 'cheaper', so let's start by thinking of what we want to achieve.
What are the NAS Software Requirements ?
A1. NTFS & RAID.
Your NAS software must support NTFS formatted drives in a RAID configuration.
RAID means either a RAID-1 MIRROR pair or a 3+ disk RAID-5 set. If you go 'Mirror', there's a cost advantage if your NAS Operating System offers software MIRROR support (to maintain performance, RAID-5 must implemented in Hardware, most likely using a PCI card, so software support for RAID-5 is irrelevant).
Software RAID is built into all versions of MS Operating System, however it is only 'enabled' in the Server versions (of which more later).
NTFS is a 'must' because I have never, ever, known an NTFS formatted disk to suffer from a 'corrupted directory', whilst my FAT 32 formatted devices (eg. USB Memory sticks) fall over every other month. If anything goes wrong with one of the various clever LINUX/UNIX formats (XFS or EXT2FS etc) you can more or less forget your data (your drive will have ..).
A2. No Internet.
To protect your NAS from the source of most virus infections, it must be totally isolated from the Internet. So whatever software you use, must run 'perfectly' without needing to 'phone home' at regular intervals (to Microsoft, or anyone else) in order to get regular "bug fix's" or "security update's".
If you have a 'wired' (Ethernet cabled system) - or can at least link your Router to the NAS by an Etehrnet cable - this is actually easier that you might think :-). If you are using WiFi, it is actually a lot harder than you might think :-(
A3. An 'old' MS Operating System.
Generally, the older the Operating System, the fewer the bugs. I would suggest it takes about 10 years for Microsoft to fix 'most' of the bugs in each version of their Operating System software. Further, modern operating systems are 'resource hungry' i.e. need multi-GHz CPU's and Gb's of RAM just to run themselves. Older versions of Window Server had to run from tiny low speed hard drives on CPU's running at MHz (rather then GHz) and with almost no RAM, whilst still delivering files to hundreds (if not thousands) of Corporate users.
Since NTFS is a 'must', this means NT4, Windows 2000, or Windows XP.
Since some 'modern' features (SATA, high capacity hard drives, file sizes over 4Gb) are not properly supported in NT4, in practice this means either Windows 2000 or XP (or the server versions, 2k Server, Server 2003 etc)
A4. An Operating System that will allow all your individual users to connect and use the Server / NAS 'shares'.
The non-Server versions of Microsoft operating System (2000 Pro and XP Pro) limit the number of simultaneous 'share' connections to 10 (XP Home limits it to 5).
If you want your Windows based NAS to allow connections to more than 10 other computers** (known to MS as 'Clients') 'at the same time', you will need a full Server licence (and sufficient Client Access Licences = "CAL's" to cover the maximum number of simultaneous connecting devices. You should note that a basic Server Licence includes just 5 CAL's (i.e. half the number supported by the non-Server 2000 / XP Pro software). ** whilst we may refer to the '10 user limit', the limit is actually imposed on the number of different 'devices' and NOT actual 'users' or 'Shares'. Specifically, if you map 2 'shares' and another user on your computer 'maps' a few different 'shares', this all counts as a single 'user'. Once you reach 10 different devices, further connections will be refused. However, if one computer 'lets go' of all it's mapped shares, another can now get access. So, rather than backup every file as soon as it's changed (which would mean that shares are constantly 'active'), backups should be 'staggered' and done at regular intervals, plus you should ensure the share is 'dropped' after each use.Note that you don't have to explicitly drop a share as Windows will do it for you after some period of inactivity. See here for Microsofts explanation of 'user' limits (scroll to the end for adjusting the device 'auto disconnect' idle time-out limit)
A5. Available at a reasonable price :-)
If the old computer you have chosen to use as a 'Server' has a Windows 2000 Pro (or XP Pro) licence, and you have no more than 10 devices needing simultaneous access, I suggest sticking with that (and spending your money on a RAID-5 PCI card) rather than wasting it on another MS Operating System that isn't going to work any better
If you have more than 10 users, 'reasonable cost' may be the hardest criteria to meet, however whilst eBay sellers of "Full Retail" licences try to charge 'an arm & a leg', often you can find auctions for 'spares or repairs' Hardware that will come with the licences you need for less than half the price.
The drawback, of course, is that most 'spares or repairs' Hardware will come with OEM Licences. These are versions of Windows that will ONLY run on that manufacturers Hardware. Further, in some cases the required OEM System disks will be missing and hard to obtain at reasonable (or any) cost. You should thus stick with the 'Home Office' vendors (such as Dell) and avoid the 'rip off' vendors of 'corporate level' kit (from HP / Compaq, for example).
Do you actually need a 'Server' level operating system ?
Well the primary requirement for your home server is the ability to support RAID. If don't have a RAID-5 PCI card, then I suggest you stick to SOFTWARE RAID-1 MIRROR. Unless you unlock RAID support in Windows 2000 Pro / XP Pro, this is available only in the 'Server' versions of MS Windows, so "yes you do".
On the other hand, if you ARE using a PCI RAID card, then for sure, "no you don't" need a Server version of Windows - and, in fact, you MAY be able to 'make do' with the version of Windows the box came with = if it's Windows 2000 Pro or XP Pro, 'yes'. If it's Windows 98/Me (or Vista), for sure 'NO'. If it's XP Home then 'maybe' (if you have 5 devices or less).
Where to source your Windows Server software ?
Plainly Microsoft has zero interest in selling you last years software, let alone a version more than a decade old :-) .. and only naive child (or the insane) would risk downloading a 'cracked' Operating System from the virus, key-logger and root kit infected 'Torrents'.
So let's start with "Full Retail" versions (on eBay in mid 2011) :-
(a)'Full Retail' NT4 Server + 5 CALS (i.e. supporting 5 users) with sp4 (Service Pack 4), approx £50
(b)'Full Retail' Windows 2000 Server + 5 CALS, approx £120
Whilst the NT4 may be 'cheap enough', we would like the Win 2000 .. and that seems way 'over the top' especially as it only supports 5 users (= half that of W2K / XP Pro & same as XP Home). Of course, a 2003 Server Licence would be even better, however there is a high risk of it being Counterfeit.
So the next step is to look for a cheap Server box with a Server Licence 'included'. A quick search (Sept 2011) turned up the following :-
(a) 'Spares or Repairs' Dell PowerEdge 2500 with Windows 2000 Server licence, 'Buy it now' £25 (pick up only)
(b) 'No name' Server tower (SCSI) working, Win2000 Server, 'Buy it now' £79 (delivery included).
(a) The Windows 2000 Server licence that comes with the Dell PowerEdge will be an 'OEM' licence. This means you are only licenced to run that software on kit manufactured by Dell.
To enforce this, if you use the Dell Server Operating System CD to install on a non-Dell box, toward the end of the install sequence, when booting into windows, it will look for the Dell BIOS signature on your motherboard. If that signature is not found, the install / boot will be aborted.
Further, if you try to use the 'OEM' Licence serial number with a 'Full Retail' Server CD (which won't include any BIOS checking), you will find that the OEM Licence number is not recognised and the install will fail with an 'Invalid Licence' error.
If you have a Dell computer you intend to use as your Server / NAS (and can collect), system (a) is a bargain !
(b) The 'No name' Server MIGHT include a 'full Retail' Licence, however it's MUCH more likely to be another OEM version from some obscure vendor that is no longer in business.
Further, whilst it may be 'working', system (b) has a motherboard that is likely limited to SCSI drives (for example, Compaq / HP). SCSI hard drives are not only prohibitively expensive (because only Corporations still use them) but also only come in 'tiny' sizes (35Gb is common).
Also, many corporate level Servers have 'dual power supplies'. This sounds 'cool' until you realise that the most likely thing to go wrong (after the hard drives) will be the power supply - and that a corporate Server PSU replacement is going to cost you a fortune (a standard PSU is not going to fit because the manufacturer will have made 'customised' motherboard with non-standard power connectors). Far from being a 'bargain', system (b) is actually a liability. Don't be tempted !
So, in conclusion, I suggest you stick with (1) Windows 2000 Pro, or (2) Windows XP Pro (running on an old desktop / tower) as your 'server'
Is w2k Pro better than XP Pro ?
"Stop Press" = end 2014. XP Pro is now 'out of support', so whilst 2k is still the 'lower footprint' choice, if you want DLNA and USB support you should go for XP. Of course, if you have sub GHz CPU (and less than 1Gb RAM), 2k is the only practical choice
Windows 2000 Pro is 'lacking' most of the multi-media crap that MS used to 'bloat out' XP, so has a far smaller memory 'footprint' (i.e. will run in much less RAM). Further, MSIE was far less 'integrated' into the OS (so it's simpler to 'extract') and w2k pro is no longer 'supported' by MS = so you will never be tempted to 'access the Internet' to 'download Updates'. You can thus 'block' a w2k Pro system from the Internet and dedicate it to archiving your music & photo's etc.
One drawback with Windows 2000 is it's lack of support for SATA drives at installation time. Fortunately, building a custom cut-down W2k System CD, or using nLite, to 'slipstream' drivers it's a relatively easy job to create a 'replacement' bootable System CDAnother issues with w2k is it's poor USB support - however as USB 'sticks' are a well know source of viruses, perhaps that's an advantage :-)
Is it worth trying to repair a Server from eBay ?
Generally NO. The seller will have already discovered that economical repair is impossible - that's why they are selling it as 'spares or repair' :-)
The most likely problem will be a faulty power supply that has 'fried' the motherboard. Since all older Server motherboards are 'custom' designs (and Servers were only sold to Corporations), a replacement, even if available, could cost over £1,000. The motherboard mounting, case fans & air flow and the power supply(s) (and it's connections) will all be 'proprietary' (i.e. non-standard), so nothing in the case (& not even the case itself) will be 're-usable' :-(
Many older servers supported only SCSI disk drives and had motherboards that required 'low capacity' 'Parity' RAM (which you often see offered on eBay with £0 bids)
The 'exception to the rule' is Dell Servers sold to the 'SOHO' market over the last 5-8 years or so with XP 2003 Server or later = these 'low end' Servers use 'standard' components (but often still require 'parity' RAM). However watch out for the older Dell Windows 2000 Servers boxes = these are (almost) as 'proprietary' as HP / Compaq :-(
Any tips on Operating System install options ?
Yes = always select 'custom' install (you don't want the Games, etc.)
IDEALLY your should build a CUSTOM install System CD (using software such as a nLite) in order to prevent unwanted crap being installed in the first place
For Servers, the basic 'mode' is also important. When asked during a Server Operating System install, you MUST choose 'Data Server' NOT 'Domain Controller' (or Backup Controller).
Your home network will be using the 'WORKGROUP' network configuration NOT a DOMAIN. Domains are a pain to set up and maintain and whilst you get more 'control' they also require a lot of 'maintenance' (which is why companies employ full-time IT staff)
If you are using a non-Server operating system & have the 'option', choose install 'For a Laptop' = this will prevent the OS setting up and turning on all sorts of power wasting and resource hogging 'Services' the only function of which is to ensure your PC is always 'busy' (thus virtually guaranteeing that in the event of sudden power loss your hard disks are corrupted).
Windows XP on a desktop is known to 'read' it's C: disk every hour or so thus preventing the drive from powering-down. The 'culprit' appears to be the the csrss.exe process (not to be confused with the Trojan/Worm csrrs.exe) however it does not do this on a laptop !
Microsoft says 'csrss' is the "Client Server Runtime Server Subsystem", however this is the usual MS nonsense = it has nothing to do with your network :-) Rather, when a user-mode process calls a function involving console windows, process/thread creation, or Side-by-Side support, instead of issuing a system call, the Win32 libraries (kernel32.dll, user32.dll, gdi32.dll) send an inter-process call to the CSRSS process instead. This avoids 'compromising' the kernel (although Window manager and GDI (graphics driver) services are handled by a kernel mode driver (win32k.sys).
In mobile devices such as notebooks and laptops, csrss.exe is dependent on power management schemes implemented by the system as defined under the Control Panel option (and the 'Screen Saver' settings). Whilst this 'explains' why csrss is not performing constant 'reads' on a laptop, it does not explain why it has to perform these 'reads' on a desktop.
Note that a corrupt 'user profile' can cause csrss to grab 100% of CPU resources = see Microsoft KB555021
How to update the Operating System and Drivers ?
Your Server should never be connected to the Internet, not even to set it up. So you will have to download all MS updates etc. using your 'main' computer. You will need to make sure you get the 'network install' Service Packs etc. from MS. One of the most vital things to get will be the most up-to-date drivers for your network card (the NAS data trasfer bottleneck is going to be your network, not the hard drives). All the Service Packs, updates, drivers etc. should be 'burned' to CD / DVD and kept with the Operating System CD = you will need** them again in 5 years time when your C: disk fails
** If you have to re-install after a C: drive fail, you want to restore the EXACT SAME system that worked previously. Experimenting with new device drivers etc. when trying to recover your data is NOT a good idea :-)
Start by going to the Microsoft Web Site and download the 'network install' version of the latest available 'Service pack' for your chosen Operating System (the 'network version' is sometimes marked 'For Corporate IT use' or 'Network Administrators'). This will be a 'self installing' archive that can be burned to CD.
Note that Microsoft stopped supporting Windows 2000 on July 13, 2010, so you can expect no new updates. The advantage of 'no new updates' is 'no need what-so-ever for MSIE' (nor a whole host of other useless 'Services')
Go to the computer Manufacturers site and download the latest available drivers for the motherboard. Visit the sites of the manufacturers of any PCI card you have installed (NIC, RAID) and again get the latest drivers (most cards are shipped with a drivers CD that is obsolete before the box even reaches the vendors shelves).
If you have a Gigabit Ethernet router / hub, then your Sever should be equipped with Gagabit Ethernet. Few older boxes had motherboard built-in Gigabit, so invest in a £5 PCI card
Go to the Network Interface (NIC) 'chip set' manufacturers site (typically Intel) and download the latest Network drivers for that chip set.
Often computer manufacturers fail to update their own software to include the latest chip-set drivers. Since you are building a data server, Ethernet performance is vital and having the latest drivers can make a significant difference to network data rates.
Using the latest Intel drivers I was able to set my (Dell motherboard integrated) Ethernet to run almost twice as fast (essentially, by increasing the NIC 'packet' sizes and 'pipe-line' type options to the maximum)
If you have Windows 2000 Pro or XP Pro and want to use software RAID (MIRROR) for your data disks, you will also need a 'Hex Edit' utility (to 'turn on' RAID MIRROR support).
Burn all this to CD and then use the CD to update the Server in the following order :- Windows Service Pack first, reboot, then motherboard drivers, reboot, then chip-set drivers & then a final reboot.
How is the Recovery Console used ?
The Recovery Console can be started from the Operating System distribution CD, however it's plainly more convenient if you have pre-installed it
Note - if you have Windows 2000 Server and have MIRRORED the Operating System disk (C:), see Microsoft knowledge base article first
Open a 'cmd' windows, insert your Operating System CD, change directory to the CD drive and type winnt32 /cmdcons to install the console
See here for Microsft knowledge base article on usage of Recovery Console
How do I make a 'System Restore point' with Windows 2000 ?
System Restore was not available with Windows 2000 (or earlier) - instead you have to do a 'System State backup'. This is performed via Start / All Programs / Accessories / System Tools, Backup. Select 'System State' in the 'what to backup' options.
To do a System State Restore you have to reboot and F8 into Safe Mode. From there you go to the Backup system tool and choose 'Restore', 'System State'.
Note that installing Windows 2000 takes ages. So as soon as you have a working Windows system, make your first System State backup. Do it again after disabling pointless services, again after installing the data drives and again when it's all working and you are about to remove the Keyboard/mouse and monitor.
TIP. Windows 2000 may ask for a FLOPPY DISK to store the system details on. Some more modern motherboards have a BIOS setting that allows you to 'emulate' a Floppy Disk using a USB stick.
How do you enable RAID MIRROR in Windows 2000 (& XP) Pro ?
Note = the following is illegal in USA, where the Digital Millennium Act prohibits you from 'modifying' the Operating System in any way 'not intended' by the vendor (and that would include changing the disk manager settings needed to enable RAID)
AFTER you have installed the latest Service Pack (and, in case something goes wrong, the Recovery Console), you can enable RAID-1 support in Windows 2000 Pro. It is achieved using a Hex Edit utility on the 3 disk manager (dm) system files to change the setting from 'normal' mode to 'server' mode (note == ALL this does is allow the disk manager to use the built in software RAID functions - it does not turn 'Pro' into Server').
Start by locating and making copies of the 3 files involved (a good place to put the copies is in the 'root' of C:) :-
(from system32) dmconfig.dll
(from system32) dmadmin.exe
(from system32/drivers) dmboot.sys
Using a hex editor, SWAP the string sequences ('SERVERNT' <> 'WINNT') around.
i.e. locate the string 'SERVERNT' (or 'servernt'), delete it and insert 'WINNT' (or 'winnt') in it's place.
Then find the original string 'WINNT' ('winnt'), delete that and insert 'SERVERNT' ('servernt') in that place.
Make sure you DELETE the original string and then INSERT the replacement in it's place - if you 'over-type' there is a danger that you will leave behind parts of the first string, whilst overwriting codes beyond the end of the second. Swap the modified files with the originals (i.e. keep a copy of the originals in case something goes wrong), then Reboot If anything does go wrong, power cycle and choose the Recover Console & then put the originals back
How do I increase the number of 'simultaneous users' ?
First, DO NOT be tempted to 'download' some virus/root kit infected 'krak' patch of TCPIP.SYS (this does NOT change the 'incoming' connection limit anyway, only the 'outgoing connection attempts per second', which MS limited in XP sp2 to 'slow the spread of viruses' = i.e. to limit the ability of your root-kitted computer to commit DDOS attacks on others via the internet). If you must change the limit, it's only necessary to modify a Registry Key (see A4 below)
Hopefully this warning will stop you being 'key logged' & 'root-kitted' (unlike the moron at forum.notebookreview.com who reports how he disabled his anti-virus to install the TCPIP.SYS 'krak', despite his PC screaming 'VIRUS' at him, and who, no doubt, is now wondering why his Bank & PayPal accounts are empty) ..
A1. Other than purchasing a Server Licence (plus additional CAL's) or switching to a LINUX based server, there is no 'legal' way you can change the actual 'count' limit = the 'simultaneous user count limit' really is part of your XP Home / Pro License (RAID, however, is not mentioned)
Remember that the 'limit' is actually the number of DEVICES that are allowed to connect to a w2k Pro / XP Pro system 'at the same' time'. In today's networked home, it's actually quite easy to run into that limit - for example, a photo-frame fetching photo's, 2 DLNA 'boxes' playing music or movies plus a couple of desktops and a collection of laptops/tablets/smart phones all wanting to 'back up' or access media files at the same time & you will soon have reached the limit !
A2. However you can adjust the definition of 'simultaneous' by changing the idle time-out 'AutoDisconnect', as per Microsoft KB314882. The default AutoDisconnect time is 15 minutes - this means that, unless the device EXPLICITLY 'unmaps' a share, it will continue to be 'counted' against the '10 user limit' for 15 mins after it stops using the share
Note that AutoDisconnect has no effect on the visibility of the 'share' (i.e. it does not 'un-map' the share at the client) - when the 'timed out' device next tries to read/write the share it will be transparently granted access (or at least it will be if the 'simultaneous' limit has not yet been reached)
Go to 'start', 'run', 'cmd' & type :-
net config server /autodisconnect:{time_to_disconnect}
the {time_to_disconnect} is in minutes, 1 the minimum (which is a good choice for those running into the limit)
Unfortunately, most DLNA boxes are totally 'brain dead' and will crash if they get 'disconnected'. So, if you have any DLNA players 'connecting' to your Server, you will have to leave the 'timeout' at 15 (or may even have to INCREASE it) to avoid your DLNA boxes falling over
A3. Your 'home built' photo-frame and all your desktops/laptops can be 'scheduled' to run their 'fetch photos'' or 'back-up' script at different times - and all your scripts can be set to 'disconnect the share' as soon as they have finished (using NET USE /DELETE). This will keep down the number of 'simultaneous users' and should allow your 'Server' to support well over 10 devices in total
A4. Finally, if you are using w2k Pro you may be interested to know that the 'simultaneous user' count is 'set' by the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\cachedlogonscount key (50 is the max, 0 means 'limit disabled').
Of course manually changing this value on a non-Server system invalidates your 'Pro' licence (and, no doubt, leaves US Citizens open to persecution under DCMA law)
Some commentators suggest that w2k Pro is incapable of supporting 'large numbers of users' (i.e. more than 10).
This is total nonsense = leaving aside, for one moment, the fact that there is essentially zero difference between 2k Pro, 2k Server and 2k Advanced Server 'core' code, there is also the fact that MS believes Windows 2000 Pro can support 10 users on a 133MHz 'Pentium (1) processor' with a recommended 64Mb RAM (and at a time when networks ran at 10mbs)
This 'suggests' to me that, running on a 3GHz CPU with 4Gb RAM, w2k Pro should be quite capable of supporting 10x 22 (CPU) * 64 (RAM) = 14,080 'simultaneous' users (although that may require a Gigabit network) ...
Does 'per seat' (w2k Server) or 'per user' (2003 Server) Licensing 'allow' unlimited connections ?
Yes, that is correct. HOWEVER, whilst in 'Per Seat' (w2k Server) or 'Per User' (XP 2003 Server) mode the Server does not impose any 'simultaneous user' limit, this is because you will have already purchased a separate CAL for each and every device that could possibly connect to ANY Server on your network. So (none of) your Servers need to 'count' users (the MS Licence Logging Service is disabled by default on 2003 Server anyway)
The max. 'simultaneous users' CAL count is only imposed in 'Per Server' licensing mode. In Per Server, CAL's are 'registered' onto an individual Server & each Server tracks the actual number of 'simultaneous users' (and imposes it's own limit). Plainly, 'Per Server' mode is better when you have a single Server (which not all your users are accessing 'at the same time'), since you only need to purchase enough CAL's to meet the maximum 'simultaneous' user count, whilst in a multi-server system, 'Per User' is generally better
How do I 'active' my CAL's (and where are the serial numbers) ?
In 'per Server' mode, you type the number of CAL's you purchased into the Server Licence Manager (but not the serial numbers). In the 'per seat / per user' mode, there is no-where to enter the 'count' or the serial numbers. In both cases, you should keep your CAL 'certificates' in a safe place (so you can produce them if requested by Microsoft or instructed to do so by a Court of Law)
Note that Microsoft requires you pay for a CAL for each 'device' you wish to connect to 'their' Server, no matter if that be an Apple Mac., Android tablet or 'smart' phone / TV / Bluray player or DVR etc.
If you don't like the MS Server limitations, stick to the 10 device limit of the 'Pro' system = or install some flavour of LINUX on your Server(s)
Click 'Next >>' in the Navigation Bar (left) for a guide to choosing NAS Hardware