Recovering Data from a Failed Synology NAS
by Ganesh T S on August 22, 2014 6:00 AM ESTConcluding Remarks
My Saturday plans went haywire, thanks to the DS414j going belly-up. However, I did end up proving that as long as the disks were functional, it is possible to easily recover data from a Synology RAID-5 volume by connecting the drives to a PC and using UFS Explorer. Users wanting more of a challenge can also use Ubuntu and mdadm for the same purpose. In my case, the data was in a SHR (Synology Hybrid RAID) volume with 1-disk redundancy, but the disks were all of the same size (making it RAID-5 effectively).
Lessons that I learned from my data recovery experience:
- Have access to a PC with multiple spare SATA slots, preferably hot-swap capable
- Back up data written to a NAS frequently (if possible, in real-time)
- Have access to a high capacity DAS (with more free space than the largest NAS volume that you may have to recover)
- Avoid encrypting shared folders and/or volumes, if possible
- Prefer straightforward RAID-x volumes compared to customized (note: customized need not necessarily mean proprietary) RAID implementations and/or automatic RAID level management (such as Synology's SHR / Seagate's SimplyRAID / Netgear X-RAID2)
- In critical environments, run two NAS units in high availability (HA) mode
Things I would like from the NAS vendors' side (Synology already ticks most of these):
- Don't use proprietary RAID / hardware RAID for consumer NAS units
- Instead of (or, in addition to) supplying backup software, provide licensed versions of data recovery software such as UFS Explorer (or, supply one developed internally for Windows / Mac / Linux)
- Provide official documentation for recovering data using PCs in case of NAS hardware failure (using either commercial software such as UFS Explorer or open source ones like TestDisk)
Synology alone is not to blame for this situation. If QNAP's QSync had worked properly, I could have simply tried to reinitialize the NAS instead of going through the data recovery process. That said, for the same purpose, QNAP's QSync worked much better than Synology's Cloud Station (which was the primary reason our configuration utilized a share set up on the DS414j as the target folder location for QNAP's QSync). In any case, I would like to stress that this anecdotal sample point in no way reflects the reliability of Synology's NAS units. I used to run a DS211+ 24x7 without issues for 3 years before retiring it. More recently, our Synology DS1812+ has been running 24x7 for the last one year as a syslog server. The DS414j which failed on me has been in operation for less than two months. I put it down to the 'infant mortality' component in the reliability engineering 'bathtub curve'. Synology provides a 2-year warranty on the DS414j, and any end-users affected by such hardware issues are definitely protected. One just needs to make sure that the data on the NAS is backed up frequently.
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Impulses - Friday, August 22, 2014 - link
While I generally agree with your logic (having never given my desktop up as my primary system, and being single), saying "just plug the laptop in via TB" or whatever isn't exactly a viable alternative for many users.I don't own a NAS, but it seems to me the biggest market for units are laptop dependant and/or multi-user households... When you have a couple and possibly kids each with their own laptop it's much easier to have a centralized media store in a NAS than anything directly attached.
Gigaplex - Saturday, August 23, 2014 - link
"A consumer can just buy high availability as a service (such as from Amazon services)"Not on ADSL2+ when dealing with multiple TBs of data I can't.
wintermute000 - Saturday, August 23, 2014 - link
QFTWHangFire - Friday, August 22, 2014 - link
Losing a day's work is considered acceptable in most environments. In theory yesterday (or last Friday) is fresh in everyone's mind, and the raw source material (emails, experimental data, FAXes, etc.) are still available in their original form to redo any data entry.What is interesting about the QSync situation is the cascading affect of failures. If caught early, through log examination, dashboards, whatever, true disaster can be averted. If minor issues like sync fails are allowed to continue, and RAID failure follows, say, a month later, then a month's worth of work can be lost. That is not acceptable in any environment.
Kougar - Friday, August 22, 2014 - link
Thanks for the article! I have a ~6 year old TS-409 Pro that is still running great, but internal component failure has been on my mind for awhile now. I'll be bookmarking this in case I ever need to use recovery options on it as I wasn't aware of either of these tools!kmmatney - Friday, August 22, 2014 - link
Nice article! I use a WHS 2011 server, with Stablebit DrivePool for redundancy. The nice thing about Drivepool is that the drives are kept in standard NTFS format. You can just take the drive out, and plug it into any computer to retrieve files, so data recovery is a piece of cake.Impulses - Friday, August 22, 2014 - link
Shame WHS is now RIPDanNeely - Friday, August 22, 2014 - link
Yeah. I'm really hoping ZFS or Btrfs NASes (without huge price premiums) will be available in the next year and a half as reasonable replacements for my current WHS 2011 box.Impulses - Friday, August 22, 2014 - link
That'd be nice, I never bought my own but I recommended and set up several for various clients & family members with small businesses...No clue what I'd tell them to migrate to right now if one were to break down, the ease of recovery and expansion was one of the biggest draws to WHS and in fact the reason many picked it over cheaper NAS boxes.
Gigaplex - Saturday, August 23, 2014 - link
There's a reason it was killed off. It has some serious design flaws that trigger data corruption, and Microsoft couldn't figure out how to resolve them. It has great flexibility but I wouldn't trust it with my data.