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NAS Drive Failure: How I Dodged a Bullet

As you might imagine, I have a number of computers and related devices. For the last three and a half years, one of them has been a NetGear ReadyNAS branded NASNetwork Attached Storage.

It’s turned off now. I finished replacing it the other day, and I want to share why, some of the mistakes I made, some of the mistakes I didn’t make, and what I replaced it with.

And yes, how I dodged a bullet: a data loss bullet that had my name written all over it.

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Why a NAS?

An NAS is just a small computer attached to your home or business network, dedicated to providing storage. Rather than being connected to a single computer, like an external drive, a NAS is designed specifically so that other computers on the network can access that storage using Windows file sharing and possibly other protocols.

There are a few reasons you might consider an NAS:

  • Capacity: my NAS had 3 terabytes of storage, before that capacity was commonplace.
  • Speed: NAS devices are optimized for data access speed.
  • Sharing: network storage is a convenient way to share data among all connected machines.
  • Reliability: NAS devices usually use RAID – a “Redundant Array of Inexpensive Disks”1. My 3TB of storage was provided by four one-terabyte drives. Any one drive could die completely, and the NAS would continue to operate without data loss.

Naturally it’s the last item – reliability – the finally convinced me.

NAS drive failure: what should happen

A RAID array stores data redundantly, meaning that there is extra data placed on the drives which can allow other data to be recovered in the event of failure. The design is such that if any single drive in a RAID array fails, the array continues to work and no data is lost.

A couple of years ago I had exactly that happen: one of the drives failed. RAID arrays are often designed to be “hot-swapable”, meaning you don’t need to turn power off  to replace a drive. I pulled out the failing drive and replaced it with an identical model. The NAS did it’s magic to set up the newly replaced drive, and within  a couple of hours it was “fully redundant” once again.

NAS - Network Attached StorageAll was well.

The problem this time?

Two drives were beginning to die. While larger RAID arrays can be designed to handle that with extra redundancy, that’s not something my little NAS could recover from. But since they were “beginning” to fail, they hadn’t failed yet, and I had a chance to preserve the data if I acted in time.

Unfortunately, I came close to shooting myself in the foot on that.

NAS failure notification

An NAS is a nondescript box into which you plug power and network and nothing else.

That means it needs other ways to alert you to problems. The technique here was pretty simple: the NAS would send email whenever anything went wrong. That worked when the single drive failed earlier; I got a message in my inbox that said, in effect: “Pay attention to your NAS or you risk losing data”. I acted on that, replaced the drive, and life went on.

This time I got no message.

The drives could have been on their way to failure for months, and I wouldn’t have known about it.

Why? The NAS had become unable to send email. Even now, I’m not 100% sure what changed or why, but as I looked at its email settings, it was clear: that configuration wouldn’t work. It probably worked at some point, but right now, when I needed it to, no.

The message that it was trying to tell me? “Pay attention to your NAS soon or you really risk data loss.”

The only reason I stumbled onto it is because the NAS also starting crashing when it attempted to read a specific file, and as a result attempts to use the NAS from the computers on my network were failing. Not only should a crash never happen to an NAS, it’s a Big Red Flag if it does. It was probably related to the impending failure.

The dilemma I faced

I was now faced with a choice. I could:

  • Replace the two failing drives in the NAS, one at a time, so that the NAS could rebuild each in turn, and hope it would complete the process before one or both drives failed completely.
  • Ditch the NAS and replace it with a single external drive.

On one hand, keeping the NAS running seemed like a reasonable choice. Except that it’s another device, with four hard drives that could fail. Of the five hard drives it had held since I got it, three had failed or were failing.

On the other hand, replacing it with a single, simpler drive – and a larger one at that – attached to a computer I already had running also seemed like a pretty compelling option. I really don’t need the speed and redundancy of a NAS or RAID; I just need some disk space.

The cost, as it turned out, was almost the same either way.

But Leo, don’t you back up?

Now, with all the harping I do on backing up, you’re probably asking yourself why I was concerned at all. I mean, certainly I had a backup of everything, right?

Yes. But.

The NAS itself had been getting backed up nightly. By that, I mean that all the data on the NAS was getting replicated to another system. So data on the NAS was unlikely to be lost, no matter what. Backups are good that way.

The problem was this: the drive had been failing (and crashing) for “a while”. By my estimates, it’d been having a problem for a month or more. And that NAS device was the backup drive (my “external backup drive”) for several of my other systems. Those devices hadn’t been getting backed up properly for at least a month.

I stood to lose my most recent months’ worth of updates and changes should they also fail while the NAS was broken.

What this means for me

I went the external USB drive route. I purchased a USB3 interface for an older desktop computer that I run in my basement (my previous primary machine), and after confirming that it worked, I ordered a five terabyte external USB3 drive. I did some more shuffling for performance: the internal 3TB drive that had been the backup for the NAS now became the NAS’s replacement. The external USB drive became the backup to the NAS drive.

It’s no longer an NAS in the formal sense, since it’s not a dedicated box with multiple disks in a RAID array providing only storage. Now it’s just a drive shared by a PC on my network.2

My lesson was pretty simple:

  • Don’t break the way that devices might notify me of a problem.
  • Make sure that backup processes that fail notify me somehow. (And that I pay attention to those notifications.)

Being as email-centric as I am, that means don’t break email. :-) And set up filters so important emails like this don’t get sent to spam.

What this means for you

So why am I telling you all this?

Two reasons, really:

First, I want to reassure you that this kind of thing happens to all of us. No, I’m not expecting that you have a NAS on the verge of a nervous breakdown – but you may have a hard disk in your machine that could be. The warning signs are easy to overlook or ignore. The bottom line here? There’s nothing like a good backup to protect you from anything.

Second, I want to remind you that hardware breaks. People often assume that nothing could possibly break when it comes to their computer’s hardware. Even when the symptoms are clearly hardware related3, people continue to ask “where’s the setting in the registry to fix this?” It doesn’t always work that way. Hard disks fail more often than we’d like, and often at exactly the wrong time. Computers, keyboard, mice, monitors … they can all fail, in various ways from boring to exciting, and it’s important that you realize this and be prepared.

On one hand, I can look at my scenario and point out places where I failed to sufficiently protect myself – and indeed, I’ll be making a change or two as a result. When you’re working with technology, there’s always something that can be tweaked or improved.

But on the other hand, my system worked. I was lucky, but I was also prepared. I was backed up. There’s enough redundancy built in to my set up that I could have lost my NAS, and all three terabytes of data, on it and not be horrifically put out.4

Do this

Take a look at each component of your computer, your data, and your online life, and ask one simple question for each: what would I lose if this went away instantly and without warning?

Then decide if that’s something you want to prepare for.

My vote, of course, is that you do.

Do this

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Podcast audio


Footnotes & references

1: Also “Redundant Array of Independent Disks”.
2: For those who care: a PC running Linux Mint, though it would work just as well running Windows. It also does run Windows – in a virtual machine – for some other purposes. Ironically, the NAS was also running a variant of Linux internally.
3: I realize that’s a risky statement. What’s obvious to me may not be obvious to the less experienced. But registry settings shouldn’t be the first thing you think of when a key on your keyboard stops working either. :-)
4: The risk was that something else could die while the NAS was broken. Then I could have been in a world of hurt.

36 comments on “NAS Drive Failure: How I Dodged a Bullet”

  1. When you replaced your NAS was there a particular reason that you chose an external USB drive vs. using a drive that same size internally in the computer that holds the network data?

    • I use a NAS also, from QNAP. Same configuration, 4 1tb drives in a 3 drive array. I also have a USB3 Plugable external cradle with a 3 tb drive for backup. I have had a drive in the array fail, and the 4th drive took over like it was supposed to. I back up my wife’s PC to the NAS also, (I work directly from the NAS), then back up the NAS to the USB cradle on a regular basis. Unless I see something wierd, then I do a backup immediately. To make it convenient, from a DOS prompt, I use the xcopy command and point to the correct folders, let it run and walk away from it. I also use the xcopy command on my wife’s desktop PC, and run it also, , to her designated folders. I use something like this…

      echo (this shows me what is running. “echo off” hides the DOS window)
      xcopy /D /E /Y c:\Users\%UserName%\Documents\*.* \\SCCNAS\Data\Users\%UserName%\Documents\
      xcopy /D /E /Y C:\Users\%UserName%\AppData\Local\Microsoft\Outlook\*.pst \\SCCNAS\Data\Users\%UserName%\Outlook\
      xcopy /D /E /Y C:\Users\%UserName%\Desktop\*.* \\SCCNAS\Data\Users\%UserName%\Desktop\
      xcopy /D /E /Y C:\Users\%UserName%\Downloads\*.* \\SCCNAS\Data\Users\%UserName%\Downloads\
      rem logoff /s /t 30

      “rem” means remark. It does not run that individual line of instruction. To see all the commands to use and run xcopy in a DOS window, type “xcopy /?” (without the quotes).
      The last line which is remmed out, logs the PC off after 30 seconds. You can also use the shutdown command instead of logoff command, to shut the PC down after the backup is finished.
      This all is not difficult to set up, and works well.

    • I’d run out of power cables and SATA connections internally on that box. :-) It already has three internal drives. I could have added more, but it would have been too much work compared to the effort of “buy it, plug it in”. So it currently has three internal drives (1/1/0.5 TB) and three external (1/3/5TB).

  2. I have purchased a Western Digital 4 TB NAS drive. I have not set it up yet but I don’t think it has a Raid array. I think it is just network connected. It does have a USB 3 connection so I can back it up which I intend to do weekly. I backup my Library folders via windows 8 File History right now daily to a USB 3 external drive.
    Once a week, I just clone my desktop drive (1 terabyte partitioned with Windows 8 and Windows 7) to an 3.5″ drive using a Connectland dock. This way, in the case of failure, I can just switch drives, restore the latest version of my files from the File History device, and be back running in 30 minutes.
    My background (before retirement) was mainframe software management so backing up data is done religiously.
    Glad you were able to recover your data.

    • That is very interesting. My background is also mainframe support, and backing up data is done religiously.
      My laptop (desktop replacement type) have an SSD for windows and everything else is n a platter drive
      in bay 2. I use acronis and have its end of backup exit copy the new .tib file to a second external 4tb drive.
      I’m looking at Seagate’s new 3 / 4 / 5 TB single bay NAS (Personal Cloud) for media storage, it offers a number
      related services like Samba, FTP, DLNA, SSH (for SCP and secure FTP) as well as ability to access the device
      over the internet securely. It has a USB3 port to attach additional storage and has built in support for backup
      recovery with that drive . Since the data duplicated elsewhere (except for whatever samba shares are defined)
      and they are backed up to the external drive. It should be fine. It is offered in a 2 bay model but since its
      consumer grade, they say its not field fixable, (the failed drive would mean replacing the whole thing in warranty).
      Single bay makes more sense for my needs.

  3. Dear Leo,
    Interesting article about the NAS. I had considered buying one, but was put off by cost and went the external (USB-connected) route, but with a twist:
    My main office machine has a second drive, so that is shared as my “network data” drive.
    I run batch files to copy contents of the network data drive (Y: mapping) to the external 1Tb USB drive (G:) and to my laptop.
    Basic example: xcopy “Y:\*.*” “G:” /D /E /C /H /R /Y /EXCLUDE:Y:\EXCLUDE1Tb.txt
    The EXCLUDE1Tb.txt file lists folders not required to be copied such as “$RECYCLE.BIN”, “System Volume Information”, etc.
    When I go to my girlfriend’s house, I take the laptop and backup the “network data” to another external 1Tb drive.
    The backup is scheduled daily, but can be run whenever, I do any significant data changes.
    Not perfect, but simple and very effective.
    Keep up the good work.

  4. Hi Leo, I have had the same thing with a NAS unit, BUT, what I found was the power supply was the issue.
    Voltage was not steady. I replaced the adapter with a new one and was able to continue on as the drives rebuilt.
    All to often, starting with “Lacie” external backup units, has it been the A/C adaptors.
    Just food for thought………

  5. Instead of USB, since my computer case has 2-5.25″ drive bays, I installed a tray in the empty one which accepts 3.5″HDD, supposedly hot pluggable (it sorta is, the BIOS is correctly configured) and I have a set of 1 and 2 TB drives I use for backup. I even use one as a second Edit drive for specific photo projects. Several are Enterprise Drives. The weird part about the Enterprise drives is when they are running data, their temps hit close to 60C. WD considers this “normal”.

    To avoid problems, I only swap or remove a drive in Sleep mode. No problem inserting a drive hot. There is no notification available for pulling the drive as there is with USB.

  6. Back about 1998, we got our first RAID array, 4 x 4 GByte disks, giving 16 GB total; or as indicated by Leo, 12 GB effective.

    One of the disks failed; and we ordered up a replacement, taking the identification information from the failed disk, which was also identical to the other three.

    Waiting for the replacement to arrive, we carried on working with the other three.

    When the replacement did arrive; and cross-checked by its labelling to the other four as being the correct one, I went in particularly early to put it into the empty slot in the array.

    Having done so, switched the machine on – wouldn’t boot, yet had been working fine immediately previously – 24 hour running.

    Running down, switching off and removing the replacement disk did not cure the problem.

    It transpired that the replacement disk, identical Type Number etc, was somehow different.

    The machine manufacturer could not tell us how to recover with the three remaining disks – which previously had kept things going.

    Two colleagues managed to work out how to restore the three remaining disks, so at least we were back on air.

    Eventually we did receive a proper replacement – plugging it in with some trepidation.

  7. I try to backup pretty regularly but there is always a slight possibility of computer / drive problems. One thing occurs to me. SSHDs are now getting affordable even in large (1tb) sizes. They appear to be much more reliable with min normal 10 year to failure times quoted by some manufacturers. I wonder however what are the chances even if they do fail to write of not being able to read them. If the ability to still read the data remains when they no longer write then the confidence in the backup is raised several levels. What do the experts think?

    • My understanding is that

      1) magnetic hard disks still last longer
      2) when flash memory fails it often fails completely (i.e. both read and write)
      3) flash memory offers almost no recovery options that compare to some of the advanced techniques used by data recovery services.

      Bottom line: my assumption is that when flash memory dies – regardless of its type – its contents are gone. Period.

  8. I have understood, leo, that a weekly backup to a second hdd would handle this problem, particularly if the hdds were not connected by RAID (virus contagion). As a simple PC citizen, I would imagine I’ve missed something here?

  9. I had a “happening” with my Synology NAS a few months ago. (I chose Synology because it was recommended for a mixed Mac/Win environment). During a thunderstorm which caused a blackout, the NAS packed up. I worked out that the OS on the NAS was gone somehow, so I reloaded it. I then found I couldn’t access data on the drives. I removed one and dug up a program which could read the format and retrieved most of the files. I later found that the other drive was OK, but it was a useful exercise. The problem was that my NAS was the backup and also the source for my common files, and there was no backup for the NAS.
    I replaced the faulty drive, invested in a UPS, and instituted backups for my common files back to my laptop. I also found out how to stop TimeMachine from gobbling all the disk space. I think I’m secure now but with time pressures it took a couple of months to achieve that, during which I was vulnerable.
    Another thing I learned along the way: if I tell Macrium to back up my C: drive, it doesn’t include my user data (something to do with permissions?) – I need a separate backup for that.

  10. Hi, I have been through a horrible external 3TB USB hard drive failure, which started intermittendly with some data loss, but expanded to much worse later on. I managed to recover quite a lot of data (but not all) with Easeus Data Recovery software (Not Cheap), and I am pleased with the investment. I had no backup data because I caught out. When I checked the faulty USB HDD later, it had died all together. How does one backup a 3tb usb hdd when there is little space elsewhere to store the backup. I decided to invest in another USB HDD of similar size so that I can safely backup or duplicate my data hdd.
    Some of the backup software I tried was proprietary, and failed to recover lost data, and some of the cheaper variety worked ok, which later on required a fee to be paid if one wanted to recover data. All in all, I have not had much joy with steady and safe backup software. What is a man to do? Cheers

  11. Leo, I recently built a serious video graphics box so that I can process HD video in near real time. I have a 512 gig SSD which I like very much. I always back up using Macrium and am happy with the software. My question is this: I “restored to another disc” option in the software and restored my image to a standard magnetic hard drive, a 1 Tb. model. The computer though would not boot from the disc. The back up is good as I have restored my SSD with the same image with zero problems. Can you tell me what probably went wrong and why it would not boot from the 1 Tb. drive? Mike

  12. The advantage of a NAS drive is it’s protection against things like the Crypto-Wall virus! This hits ALL drives that have a drive letter…even mapped ones! Whereas if you use a location (i.e \\NAS\Backup) it’s NOT encrypted or infected! As long as there is a drive letter…be it internal or external…it’s toast!

    Just a thought…

    • That’s true only for some variants of the Crypto-Wall family of viruses. Not all attempt to reach out to other drives.

      And technically speaking this isn’t an advantage of NAS – what you describe is an an advantage of using “UNC” connections rather the drive letter connections for accessing any network share, NAS or not.

  13. For the less High Tech people I recommend Karen’s Replicator for running scheduled copy commands around your PC drives and networks. Its freeware and is very flexible. Any comments?

    • I have used Karens replicator for a long time and highly recommend it. For one thing, the backup files are in plain vanilla format, you do not need Replicator to see them or restore them. The logging is also fairly extensive. There is an option when it comes to dealing with deleted files in the source/input folder. You can either delete them in the target/backup folder or not. And, look into the tags feature, I use it keep an entire replicated backup for each week of the month. That is, over time, it cycles through 5 different backup copies. The one downside is that Replicator does not do versioning, you can’t tell it to keep the last x copies of files.

      Karen Kenworthy, the author, has passed away so don’t expect updates. But the program is tried and true.

  14. Leo,
    Potential replacement for NAS:
    I am running Win 7 Pro 64 bit on 256 GB Samsung SSD C: system drive , an Asus Z97 Pro mobo with a i7-4790K CPU, 32 GB RAM, and a EVGA GTX-970 SC video card. I currently have separate data HDDs each for Docs, Music, Videos/Pictures. Upgrading to Win 8.1 Pro ; piece of cake.

    Ever since I first learned of Win 8.1’s ‘Storage Spaces’ feature (no upper limit for number of physical HDDs) I have been thinking this feature could fulfill the ‘file server’ duty of a NAS.

    I have spare tower case which will contain twelve to sixteen 3.5 in HDDs. I have six spare 3 TB SATA HDDs available.
    I believe I will need a PCIe X4 card to provide four port-multiplier capable eSATA ports to allow connection of the six to sixteen HDDs in the second tower case to my mobo in its (first) tower case. I have a spare 750 watt PSU.

    What sixteen SATA HDDs capable port-multiplier device will I need in the second tower case (with the six to sixteen HDDs), and do you think this approach is workable.? Will the Win 8.1 ‘Storage Spaces’ feature recognize the SATA HDDs in the second tower case?

  15. This post had several offers for “10 Reasons Your Computer is Slow…” but seemingly only for new subscribers. Can an old subscriber get a copy somehow? Thanks, Bob

  16. I have 12 of 1tb drives – 6 store different data [ programs – video – documents etc ] and the other 6 are the back ups. Since I back up once a week, the back up drives are not active [ USB & power disconnected ] because I learned long ago that even with the back up drives on line, they are prone to wear and tear as though they were accessing data but really not doing anything. I dont need the drives spinning up and down just sitting around mounted but appearently idle [ no read or write happening ]. This assures me that both main and backup are unlikely to fail at the same time [ which HAS happened before – particularly with WD green drives which I stay right away from now ]. Every week I envoke Karens replicator with a table of all main and backups to replicate everything [ changes to files only and it’s fast ] as well as the total ‘C’ drive and a triplicate of the registry, docs and settings, windows directory. I have replace 3 drives in the last year [ All WD :( ] with seagate drives and lost – nothing. :)

  17. For Windows users look at RoboCopy which is faster and improved over xcopy, xxcopy, and Karen’s Replicator. It is freeand if it was not installed with Windows it is available for download.

    • Good advice. My backup solution for friends who don’t want to spring for a backup program is to do a one time image backup. Then I created a script with RoboCopy commands to back up all changed user data. I pin a link to the task bar, but I also put a shortcut in the Start Menu in case of human nature’s failure to remember to press the button.

      • Do you mean that you put it in the Startup folder of the Start Menu? Otherwise, if it’s just another shortcut in the Start Menu, isn’t it still prone to user forgetting to click the shortcut and also possible for the user to click Unpin from Start Menu or Remove From This List?

        • You got it correct, I put it in the Startup folder of the Start Menu. I thought I said that, I probably shouldn’t be working that late :-)

          As for the user being prone to forgetting, that’s why I put it in the Startup folder. That way they are only one session behind in their backups. I don’t think most of the people I set up like this would mess around with the shortcuts.

    • If you are a Newsletter subscriber, just reply to any newsletter you receive in email and ask for “10 Reasons Your Computer is Slow (and what to do about it)” and Leo’s assistant will get you a copy. Otherwise you can subscribe to the Newsletter and get it.


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