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NAS, for Network Attached Storage, is a device that provides shared disk space on your network. You may already have one of a sort: your PC.

I have been reading about NAS devices lately. I like the idea of using one and would like to deploy one on my network. I have an external 250GB drive that I would like to convert to a NAS device. I was wondering if this was possible to do or not? Would I have to buy a NAS enclosure or something else?

NAS stands for "Network Attached Storage". Basically it's a device who's primary function is simply to provide storage in the form of disk space, often lots of disk space, to other computers on a network.

I, too, have been looking at NAS, and find the subject fairly fascinating. I was running a dedicated NAS for a short while, but then took it down. Once I understood what it really was, I decided that I didn't need another one.

Yes, another one.

The way I like to describe a NAS device is as a PC without the PC.

From a hardware perspective, NAS devices are very often nothing more than modified or stripped down down PCs. For example, they may not have a video display, keyboard or mouse. But inside, they're easily implemented using hardware that in other respects looks very much like a standard PC.

The "problem", if you want to call it that, is that a hard disk, by itself, doesn't really "do" networking. So additional hardware is required to interface between the network, and its many configuration options and the hard disk.

The hard disk doesn't really "do" filesystems either. That means in order to read and write files and otherwise maintain the organization of the information on the disk, some software is required to implement the file system. Again, there are various options that you're already familiar with: NTFS, FAT32, and so on.

The most common device on the planet that knows how to interface a hard disk to a network and create a file system and of course provide power to all the components is your run of the mill PC.

"... NAS devices are very often nothing more than modified or stripped down down PCs."

An excellent approach to creating a NAS device is to take an old PC - it can easily be a 500 megahertz machine from a few years ago (mine was) - and install FreeNAS. FreeNAS is exactly what you might expect: a free operating system based on FreeBSD that is designed to turn a PC into a high performance and easily configurable NAS device. It works very well. As I indicated I had an old PC that I tried it out on, and system was both easy to configure and very responsive, even on that old 500 megahertz machine. I had it running both an internal IDE drive, as well as an external USB drive. Quite nice.

And then I got rid of it.

You see, particularly with external drives, it was just as easy to plug that drive into one of my other computer and share it out. This has roughly the same effect, and doesn't require that I have, set up or maintain an additional PC or other device.

In a sense, every PC that can share out disk space is a NAS device.

I ended up dismantling that old PC and putting its hard drive into an external USB enclosure. I then plugged that into the same PC as the other, and now both are shared out and available as storage to any computer on my network.

So if PC's are just as good at sharing out hard disks, why even consider a NAS?

Well, certainly using something like FreeNAS is an excellent way of extending the life of a PC. If you're upgrading a PC, but still want to provide a central storage repository on your network without impacting any specific user's PC, FreeNAS is a pretty nifty solution.

The other end of the spectrum would be in high performance, high reliability situations. Much like the FreeNAS software, a dedicated NAS device might well optimize the hardware for the single purpose that it's intended for. For example, it might include very high performance hard drives, RAID or other forms of data protection and redundancy. The types of hardware that might be overkill on a desktop machine, but that makes a lot of sense in a centralized server with many users.

But ultimately, even that NAS device may still look like a PC. If not on the outside, quite possibly inside the box.

Article C2916 - January 30, 2007 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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7 Comments
Thor Johnson
February 5, 2007 8:19 AM

One thing that some NAS products do is monitor the SMART status.

It seems that while they were working on the Mass Storage USB stuff, they didn't have any provisions for SMART health. Nor do the firewire cabinets...

Then again, I haven't found the user's manual, so I don't know how it warns you, but after having my USB laptop hard drive click-kriick on me unexpectedly, I'm a little leery of non-SMART interfaces (even when my experience with SMART is that the drive goes from "All is well" to "You have 1 hour to get your data, starting 59 minutes ago..." -- at least it's a warning).

So, which would be better as a backup solution?
1. Convenient, attaches to the USB, with no health information? Fast, and unplug when you're done.
2. Attaches to the network (slower), emails you if it's going to die. Probably won't get turned off/disconnected as much as I'd like (no reason not to, but it will be forgotten)...

And do you think that storing the backup in PAR files (fsraid, etc) [files that are split in chunks so if one isn't readable, it can still be recovered] useful? My disks seem to fail wholesale (IE, the drive click-criik's and presto-no spinup)?

Leo Notenboom
February 5, 2007 9:45 AM

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If you can lose data when a single hard drive fails, that's not really a
backup, in my opinion. It's primary storage.

So my first recommendation would be to make sure you're doing a true,
redundant backup. That'll make whatever technology you decide less
impactful.

I tend to like drive always on. In my case I have external USB &
firewire drives that are always on - and on another box on my network.
(It's another PC that's always on for different reasons anyway.) That
way it's trivial to refer to them, or to copy something to them quickly,
in addition to my automated nightly backup procedure. Having a dedicated
NAS box just for them didn't make sense to me right now for my needs.

I like Raid, but only for data that needs to be highly available in real
time. Raid isn't really a backup solution.

I don't know your needs, but if drives are failing that often for you
(which is odd enough ... I've had one maybe two failures in 30+ years of
computing), I'd be tempted to simply get two drives, and backup to both.
Drives are cheap.

Leo
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Thor Johnson
February 5, 2007 10:03 AM

Thanks!

I've only had 2 failures this year (after 4 yrs of no dead fish), but the USB drive checking out spooked me.

It *is* planned to be a backup, so hopefully both won't fail at the same time, but without SMART info, how would you know that it failed? Should I do a "mock restore" every month (after making sure I can restore the first time) to check the integrity?

I wasn't planning on using any RAID features (and a friend of mine got bit by the RAID bug... after he deleted everything on his RAID'd system he asked me how to get the data back.... oops); I just want to know when the drive was going to fail (or if it had already failed).

Do you disconnect your backup drives (err... onsite backup drives) after the backup?
I was just figuring that if it was connected, there would be a greater chance of something deleting both the mains and the backup at the same time.

Again,
Many Thanks!

Leo Notenboom
February 5, 2007 11:38 AM

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Again, I just don't experience failure often enough to worry about
warnings. I rely on a good backup system and the knowledge that should
one drive suddenly fail without warning ... "oh well". :-) (How would I
know it failed? Backup processes would fail to write to it.)

And yes, doing a test restore every so often is a good idea. Even just a
read of the entire media every so often. (in the root of the drive:

XCOPY *.* NUL /s

will read the entire drive, copying all files to NUL.)

My drives are connected and on continuously. I've only had one case
where I inadvertantly deleted too much while my custom backup scripts
were being developed. (I do have a pair of external drives and
periodically swap them between my home and my wife's place of business
for added "off site" backup.)

I will say this about smart technology: one of my web servers has been
warning me that my drive is about to die. For a year or more. So even
then I tend to view it all with a grain of salt.

Leo
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Thor Johnson
February 20, 2007 7:31 PM

I found something: Google's report on HD reliability; it's discussed on slashdot:
http://hardware.slashdot.org/hardware/07/02/18/0420247.shtml

In summary:
Smart is not-so-smart (lots of false positives and only at ~60% chance of catching the failure).
HDD temps don't seem to have an effect.

Nifty. Now I'm not so worried about SMART. But WinXP doesn't seem to like a failing USB drive (it sits and hangs and freezes... then complains that the MFT wasn't written properly)... are there any SATA / IDE trays that are hot swappable?

Mike
May 15, 2008 6:08 PM

I've been serving files to a smallish office of some 30 workstations for the last few years using a HP basic server tower running XP2003, with 4 external hdds. 3 in situ, 1 as the primary shared drive, number 2 as a mirror of it backed up daily. 3 as a multiple backed up with several copies of the important data. The 4th drive is brought into the office on a weekly basis and a 'copy' of the primary data files are cloned using a program called 'Karens Replicator'. This mobile drive is taken away each time as an offsite copy.

If the primary drive fails, the 2nd mirror takes its place with just a drive letter change and I purchase another drive to fill in the gap.

Win2003 takes care of the folder permissions for each user and on the whole, we've had almost zero downtime thus far.

The only real problems are failing power supplies of the drives (Maxtor 250giggers). They are very crude 12v transformer types and I get probably one fail per year on average so far.

I am thinking about buying a raid fitted NAS to do away with the server part of the equation.

Do you think it sounds like a better option? Can I set user/group permissions on a NAS system?

I'd be interested to hear professional feedback on my current system and opinions about alternatives.

Rgds

Mike

Zalek Bloom
November 28, 2009 6:14 PM

I am thinking about installing NAS. Why? I have 3 PCs on the network - 2 are WinXP and one is WinXP/Linux/Mac. I want to save on NAS drive just pictures, music and some documents from all PC. This is a a home network (wired), so not every PC is turned on the same time. Currently about once a month I manually connect external USB drive and manually backup this data. I want to put a NAS drive on the network and setup some software to automatic backup once a day (I am using GoodSync software). I read about NAS drives and it is very confusing - there are many complains about drives getting hot, slow speed and crushes. Which NSA drive do you recommend? I am looking on 1tb - $200 is my upper limit.

Thanks,

Zalek

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