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Network-attached storage as a SOHO server alternative

Features available on today's NAS devices make them much more versatile -- they can even be a competitive alternative to a conventional server for a SOHO network.

The original purpose of a Network-attached storage (NAS) device was to provide storage for servers. This was done (usually) over an Ethernet/IP network. Many NAS devices still do just that; providing networked storage (via NFS or other protocols) to hosts. However, with extra computing power available these days, many NAS devices can do much more than serve storage over a network. Even a relatively inexpensive NAS can now provide many of the functions that traditionally a server would fulfill.

Notwithstanding the extra functions that a NAS device can perform, the main initial area that is of interest in setting up a NAS is protection of data. Specifically, a customer wants to protect against data loss. There are a few ways to do this. One is to back up data to tape and keep a copy offsite. Second is to use a NAS with RAID capacity to protect against a HDD failure. A NAS that has at least two drives (and most will support at least two) can be set up in a RAID 1 array configuration. RAID 1 is a mirror configuration, so ideally the two disks should be the same size.

Taking a look under the hood, many NAS devices on the market utilise a cut down form of the Linux operating system. If you have grown up using CLIs, then this may be for you. If not, don't fret: NAS devices these days usually have a web type GUI as well.

Leaving aside the NAS devices that don't use Linux (there are some), one of the nice things about having a Linux kernel is that you can use Logical Volume Manager (LVM) to set up volumes. If you want to read a little about LVM and how to use it, you can look at my previous posts. If you really want to do some serious, low-level physical device crafting, you can even use the mdadm utility. Figure A shows the output from running vgdisplay -v on a Synology DS213.

Click to enlarge.

As mentioned before, most NAS devices can run different file-sharing utilities. The common ones are SMB, CIFS and NFS. Some NAS devices will also run AFS. The extra file-sharing utilities help when you have a small office with several different types of OS.

DHCP is another feature that is on many NAS devices. Depending on how your network is set up, you can enable this feature or leave it disabled. One point, though. The IP address of the NAS should be fixed if a router is acting as the DHCP server. Otherwise you could have issues with accessing your data.

There are other features that NAS devices offer, including acting as a:

  • wireless Access Point
  • DNS server
  • email gateway
  • print server

Finally, many NAS devices offer a backup-to-cloud solution. My preference (however) is to not dispense with an old-fashioned backup-to-tape regime just yet.

When purchasing a NAS, there is one main point to consider. NAS devices don't always come with HDDs installed. The HDDs are usually purchased separately. This means checking that the HDDs are actually compatible with the NAS. Most vendors have online lists of HDDs that are recommended for their NAS.

A final consideration for a NAS is whether to use a model that does both wired and wireless, or to just use wired. Unless you really cannot use wired for some reason, I would pick wired. The main issue with using wireless are the extra security issues involved. Throughput can sometimes be an issue as well.

As you can see by the extensive feature list, a NAS device is far more than a simple place to store data. Many NAS devices now are effectively small servers. All the services traditionally offered by a server can now be performed by a NAS. They can offer a competitive alternative to a server for a SOHO business.

About

Scott Reeves has worked for Hewlett Packard on HP-UX servers and SANs, and has worked in similar areas in the past at IBM. Currently he works as an independent IT consultant, specializing in Wi-Fi networks and SANs.

9 comments
dspernow
dspernow

This article suggests using a NAS as a low-cost server alternative. Not as a backup solution. I've deployed 2-4 disk NAS solutions for SOHO environments with RAID1, but server features like DNS & DHCP were handle by ISP gateway/router. Certain NAS's are better at multi-access then others and would recommend its use in a SOHO with no more than 5 computer users.

JohnOfStony
JohnOfStony

In this article I encountered the suggestion: "One is to back up data to tape" Why would anyone choose tape as a backup medium; it's slow, exposed to dust and humidity, it's fragile (compared to disc), constantly being flexed while being read or written to, and it's very expensive by the time you've bought a drive and several blank tapes. Where I work, we used to backup to tape until in December 2004 the tape drive died. It was then that we discovered that, although the drive was less than 6 years old, it was obsolete and we couldn't buy a new replacement. Even had we been able to, what guarantee had we that the tape head alignment of the new drive would match that of the dead drive? In other words, it was likely that our backups were all useless unless we spent a lot of money getting a replacement second-hand drive and had it adjusted to match our tapes. We therefore made the decision to backup to removable hard disc. We have never had a failure and, to spread the risk, we have a different disc drive for every day of the week with Friday's being cycled so that we backup to a different Friday disc on successive weeks. This means that, even if we have a disc failure, we only lose a relatively few backups, Another point in favour of disc is that the drive is only used when that disc is in use; with tape, the drive is in daily use, regardless of which tape is being used, so wear and tear is significantly greater on what is fundamentally a more complex mechanism than a disc drive. And then there's speed of restoration. Tape is a serial medium; disc is random access so restoring a file from a backup is significantly faster from disc than from tape. Am I missing something? Does tape have ANY advantage over disc? If it does, I'd be very interested to know.

Michael Kassner
Michael Kassner

It does not meet archival standards. Two concerns come to mind: 1. Accidentally delete a file, it will be removed from both mirrored copies. 2. Disk is corrupted, the corruption will affect both mirrored copies.

jqbecker
jqbecker

Scott, thanks for putting this out - I completely agree with you. For small business, a full-feature NAS can easily replace a traditional WinTel server box. In some cases, BETTER than a WinTel server.

GAProgrammer
GAProgrammer

I'll have to disagree about cost - the tapes are only $30-40 a piece vs an expensive server grade hard drive. We can buy many tapes for basically 30 days of backups plus monthly and annual backups for far cheaper than that many hard discs. I guess it really comes down to your backup scheme and preference. I agree that the hard disc backup is far faster, but the two methods are pretty close in reliability. Even hard drives suffer from incompatible interfaces over the years (IDE, ATA, SATA, SCSI, SAS, etc).

dhanushkapg
dhanushkapg

RAID 1 is not a recommended method,Use RAID 5 or RAID 10.

gechurch
gechurch

Some applications have problems running from a NAS - I know of at least two that are not supported (apparently there are real issues that can cause data corruption under certain circumstances, it's not just a case of saying "we haven't tested it so don't support it"). Another area to watch out is if you are using offline files - I've had a nightmare trying to set those up for a small client before. Literally tens of hours down the drain. In the end I put in a desktop PC with a couple of drives in RAID1 instead. It of course worked straight away, and was a lot faster than the Netgear NAS we originally had in (that thing was awful - would only write at about 2MB/s).

gechurch
gechurch

I think it's a bit rude that someone gave you a down-vote. There's definitely still a place for tapes, but it's not in the SMB market. You have to pay at least a couple of grand to get a half-decent tape drive, then as you say a bunch of tapes on top of that. You're looking at least a few thousand dollars to get a reasonable setup. Tape solutions cheaper than this are more trouble than they're worth in my experience. In the SMB market where NAS devices are likely to exist, hard drive backup makes a lot more sense. For starters you can actually plug the drive straight into a NAS to do the backup. It's a bit silly talking about the cost of server-grade hard drives when discussing backup - no-one is buying ENT drives for backups. It's also a bit silly talking about incompatibility of hard drive interfaces. I'd expect most computer techs would have at least a few computers laying around that are capable of taking an IDE drive, and that standard has been obsolete for years. If you don't have one then you can buy an old motherboard on ebay for literally a couple of bucks that will work. By contrast there are many different tape drives - getting a second-hand drive to suit your tapes is a crap-shoot.

Charles Bundy
Charles Bundy

Is that there are two kinds of data protection scenarios. RAID is for COOP (Continuity Of Operations). That doesn't help if you want a file back that you just deleted (Chronological data recovery). Of course disk2tape or disk2disk might not help if you created, then deleted that file within your backup interval. :) To be fair to Scott I think he meant that there are two issues (COOP and Backup) but it came out sounding like RAID was one of two data backup methods. ADDENDUM: I just remembered that a guy that worked for me thought he could break a RAID 1 mirror to get a corrupted OS file back. It wasn't a bad thought since his reasoning was media defect on one, not the other, but the corruption was due to faulty RAM and got written as-was to both sides... :)