Evaluating an 8-bay Qnap TurboNAS

Qnap offers a confusing number of products in the NAS space – seventy-nine at the time this is being written.  When shopping for a NAS unit I bought one on faith as there was really very little information online (especially compared to Synology – the main competitor in the home/SMB NAS space) and overall I’d say I made a good choice.

This article is my attempt to put some meaningful information on these units out there so others can make a more educated decision.

My Shopping List

 

I have a rack of virtual machines running at a datacenter in another state, and for the last few years I’ve been backing them up to a Dell 1900 server and its hardware-based RAID6 array here in my home office.  The server was affordable when I bought it, and has been rock solid for the years I’ve used it, but it was time for it to go.  Other than its age, this thing weighs 85 pounds, is always loud, and generated enough heat that I hesitate to close the closet door because the temperatures will increase to over 100 degrees.

I was also using a Netgear ReadyNAS Ultra 6 for backups from the machines in my house, also configured as a six-drive RAID6 array.  This device has been a rock for years, but I’ve converted all our old movies to digital (accessible via Plex), and the ReadyNAS was struggling with some of the movies.

My goal was to replace both the PC and the existing NAS.  The initial plan was to buy an 8-bay NAS along with a solid-state computer to run Plex and my backup software.  Once I discovered that Qnap devices can run virtual machines natively I went with Qnap instead.  Simplicity and cost won out.

Enter the Qnap TS-853 Pro

What Qnap is selling is essentially a Linux computer with a custom case, with a proprietary software interface and the ability to run downloadable applications.  The goal is reliability and simplicity, but at the end of the day what you’re buying is a PC that’s custom-made to handle storage as its primary role, and the proprietary software that’s running on it.  That’s it.

I was looking for a (non-rack-mount) NAS that would handle an 8-drive array, and right now Qnap offers eight different models in this category, which makes this a tough decision.  Specifications differ between units, and some features seem to be disabled in software to more effectively segment the market.  I think the best way to figure out which product to buy is to figure out what features you need, and check the Qnap web site to insure that the model you’re buying supports that feature.

Differentiators include:

  • Expansion capacity.  Will you ever choose to expand the array by adding on an expansion box, and if so will you want one or more?
  • SSD acceleration.  If you’re going to use the machine as shared storage in a virtual environment like VMWare or Citrix, especially if you’re running database applications, then make sure that the model you’re looking at supports the use of SSDs for caching.  IOPS can increase by something like 2,000% if you buy the right box.
  • Virtualization station.  If you want to run virtual machines on the NAS itself, make sure it’s supported.
  • Backup options.  Do you want to replicate one to another over a network?  Make sure the box you’re looking at supports this.
  • CPU: lots of choices here, from Marvell embedded processors all the way up to Xeons.
  • Network: do you want multiple gigabit Ethernet connections that will be teamed in some way?  10G Ethernet?
  • Native Storage: How many drives do you want to have in the NAS?  Your options range from one all the way up to ten unless you want to choose a rackmount.

It took a few hours, but in the end I decide the TS-853 Pro was the best fit between cost and features for me.

Overview

My overall impression was positive.  The NAS weighs a bit under 20 pounds, and sits on rubber feet that make this very difficult to accidentally nudge or move.  The case itself is metal, and memory replacement was a 5 minute job that required the removal of a handful of screws, removal of the case, insertion of the memory, then putting it back together.  I was impressed that the innards of the device were covered by a transparent plastic with cut-outs that allowed for easy memory removal.  A note here: I put in 8 gigs of RAM because I understood that the the maximum allowable.  It turns out 16 gigs is the actual capacity, so order the larger RAM upgrade.

The hard drive sleds connect to hard drives using four screws.  This is a slower way to mount drives than some alternatives that just pop on, but I don’t see this as a real disadvantage.  How frequently do you change drives, really?

All the drives slid in easily except the 6th hard drive slot which took some fiddling to get it to seat.  I’ll be replacing it later this week and I’ll update this when I determine whether this is the case, or was something related to the hard drive itself.

Initial Install

Setup was quick and simple.  Qnap sells these devices as a way to access your data from anywhere, and the standard installation is built around that concept: go to Qnap’s web site and perform the install that way.

I don’t care for that storage model, so I downloaded installation software that located the device and walked me through the installation.  I installed the 6 2TB drives from the old backup server, added 2 3TB drives that I purchased at the same time as the NAS, and had the machine configure a single RAID6 array with a single volume on top of it.  I was given an option to choose what soft of volume to install and I chose the one that supports thin provisioning – the backup server may require 3TB of storage eventually, but it’s just a few hundred gigabytes right now.  Thin provisioning allows the NAS to report one size to virtual machines while using much less space on disk.  This is great in my environment, but it’s something that can lead to real problems as file systems grow, so stay aware.

The machine was usable within minutes, but it took over a day before all the background optimizations and volume synchronizations worked out.  This was probably due to a hardware issue.

My first drive failure

The drives I used for the initial setup of the NAS were 2TB Western Digital Green drives (I know, but they worked fine) that have been running non-stop for four years or so.  The Perc RAID controller was happy with them, but the Qnap threw up a warning that one of the drives was reporting that it was close to failure, with an uncorrectable_sector_count property value of 200.  Drive tests wouldn’t complete, so it was time for a replacement.

I looked through the documentation and ran some web searches and couldn’t find a procedure to replace a failed drive, so in the end I pulled out the bad drive, inserted its replacement, and watched the drive rebuild.

I was also impressed with the reporting from the NAS.  I received e-mails with warnings that contained:

Server Name: xxxxxxx
IP Address: 192.168.x.x
Date/Time: 2015/10/16 22:53:26
Level:  Warning
[HDD SMART] Host: Drive2 Rapid Test was cancelled.

Server Name: xxxxxx
IP Address: 192.168.x.x
Date/Time: 2015/10/17 09:08:31
Level:  Error
[Volume DataVol1, Pool 1] Host: Drive2 failed.

The reporting works.  I feel safe placing this out of sight and depending on the NAS to tell me if something fails.

A brief note on RAID levels

The Qnap supports standard RAID levels, whereas the Synology supports a proprietary and more full-featured RAID setup.  I’ll try and cover basic questions about RAID here, and explain why I prefer this approach.

RAID is a way of taking multiple hard drives and configuring them to provide a large storage pool that is resistant to failure.  If you lose a drive in a RAID array you shouldn’t lose data.  Now, there are lots of choices that you can make that offer various compromises in performance and resiliency, but as far as I am concerned there are only two worth considering at this time: RAID10 and RAID6.

  • RAID10 on an 8-bay NAS looks something like this: half of the drives are used to mirror the other drives (so drive 2 contains a perfect copy of drive one), and the 2-drive mirrors are striped together to form one big array.  This offers great performance on both reads and writes, and allows for quick rebuilds when a drive fails.  You can lose somewhere between one and four drives before you experience data loss, depending on which drives fail.  If you lose half of a mirror, then the other half fails, then you’ve lost data and will need to restore from backup.
  • RAID6 is a form of “parity raid,” where two drives can fail before data loss occurs.  Where RAID10 loses half of the native drive capacity to build redundancy, RAID6 loses 2 drives of capacity.  On an 8-drive array, that cost is 25%.  The downside is that redundancy is dependent on mathematical calculations that need to be performed when data is written or when a drive has failed in order to calculate missing data.  This means it’s slow – read performance is still fine, but writes are significantly slower than with RAID10.  When a drive fails things are much slower – in a worst-case scenario on a busy system you will be looking at days-to-weeks to rebuild the array after a drive fails, and performance will suffer in the meantime.

My personal opinion is that RAID10 makes sense as a default in business, and as a home server that’s mostly used for storage RAID6 is the way to go.  RAID5 is more efficient than RAID6, but in this era of large drives there is a not-insignificant possibility that you will experience an error while rebuilding the array that causes the array to fail.  If you run RAID5 and lose a drive, back up all the data before you replace the drive so you can do a fresh restore if it fails.  I would avoid RAID5 completely – ten years ago I installed it all the time, but in the era of multi-terabyte hard drives it’s just too risky.

Now, the Synology offerings offer what they call Hybrid Raid.  It looks like cool technology, and it offers real advantages in a home environment, but I chose to avoid it.  The reason was testing — RAID6 under Linux is well-tested and well-understood.  Hybrid RAID isn’t as well tested, and while I would bet good money that it works really well most of the time, I’ve run into too many edge cases in my lifetime to trust systems that are interesting and one-off.  I prefer less flexibility because I think it’s probably more well-tested and less likely to fail when I do something weird.

Virtual Machines

I am using Virtualization Station (an app) to manage two virtualized Linux machines that run full-time.  Overall I am very pleased with the functionality, but it’s not perfect.

  • I couldn’t make imports work.  Virtualization Station says it supports the OVF format, but exports from Virtualbox in OVF 0.9, 1.0 and 2.0 all failed.  I ended up recreating the machine from scratch.
  • Access is simple.  If you want to access the console, you can trigger a virtual HTML5 console in your web browser, or you can connect using VNC to a specific port.
  • Speed can be great.  My backup server is faster than the complete server it replaced.  It’s perfect.
  • Speed can be slow.  A Ubuntu desktop VM machine I installed is just slow.  Really, really, slow.  I haven’t figured out why yet, but network access is as fast as expected and it can run all the time so I’m happy enough.
  • Management is straightforward.  Virtualization Station is easy to use and intuitive.  Backups, snapshots, installation of VMs purchased from the VMWare or Bitnami App Stores are supported (I haven’t tested this – my brief experiment with imports from another product failed,) etc.
  • Really Stable.  I’ve had no problems with VM availability.  My VMs have been running for over a week, and even with a degraded array (more on that later) they are available and perform well.

For me this was the big advantage of the Qnap over its competitors.  The ability to run virtual machines on a Linux-based NAS solution is great.  I expect more competitors to offer this in the future.  I’m happy to report it works well, though not as a desktop replacement if you’re running Ubuntu.  I haven’t tried Windows – that looks like it has better support and may do better.

Applications

Overall the applications available are comprehensive.  The applications I was most interested in were Plex, and some method of backing up my date off-site so I don’t lose everything if something unexpected happens to the NAS.

Plex

There is a Plex application that can be downloaded using the Qnap’s management page, but it’s a little old.  I downloaded version 9.12.13 from the Plex web site, but 9.12.8.1 was the version available in the app store.  Luckily installation of downloaded apps (like the most current Plex build) is simple and straightforward.

Cloud Backup

There are multiple applications that can back up to Google Cloud Drive, Amazon Glacier or S3, and smaller players (these were the least expensive options, so they were the ones I looked at.)  These work, but like all apps of this type backing up terabytes of data takes weeks.

Amazon has an unlimited $60/year cloud storage option now, and I did successfully install this on the Qnap, but only as a mapped drive.  I can’t currently create a backup job to copy files to that mapped drive, and I’m not sure I’d want to — one of the advantages of Google Drive and Glacier is that the backups can be encrypted, and this is not supported for Amazon’s $60 option.  Apparently there’s an app in testing, but it’s not currently available.

Backups

Backups can be performed via rsync to another machine on- or off-site, but I’m using hard drives for backup.  I have things configured so that the front USB slot is used for backups, every hard drive is mapped to a particular backup job, and inserting a backup hard drive triggers the job automatically and the drive is ejected after use.  This is really simple and straightforward – much better than swapping tapes ever was in the old days.

Growing your Storage

This was one of those features that I required from the array I bought.  I believe a NAS has a longer lifespan if you can replace the current drives with larger ones and grow the array without downtime, and the Qnap supports this.  It’s not fast with RAID6 (I’m averaging about 18 hours to swap a 2TB drive with a 3TB drive and have it rebuild the array), but it seems to work well so far.

The process is pretty straightforward.  It’s so straightforward I don’t even think I need to do anything but post screenshots:

replace1
replace2
replace3
replace4

That’s just an incredibly useful feature.  In my case I wanted to leave my existing 6x3TB RAID6 array running while I brought the Qnap online using the 2TB drives that I pulled out of the server I was replacing.  Once the data was copied over and backed up, and I felt the Qnap probably wasn’t going to die from some manufacturing defect, I started moving the 3Tb drives over to the new array.

It’s not fast, but it works.  When it comes time to move from 3TB drives to something larger in a few years, I know I can do so while continuing to use the array without any noticeable degradation in performance.

Support

Contacting support isn’t an instantaneous process, but they do respond within a day in my experience.  I didn’t care much, figuring I could use the forum, but I couldn’t get registered on the forum because registration emails never got through.  This was frustrating.

In the end I registered a different name using a gmail address, and things worked fine.  Maybe it’s a misconfigured mailserver that my server won’t accept mail from.  Maybe they located the mailserver in China or Malaysia or somewhere I block.  Who knows?  Regardless, the fix was to use Gmail and registration was easy.

Conclusion

I like it.  A lot.  It’s quiet, full-featured, is successfully running as a replacement for a large power-hungry server for hourly backups from my datacenter, runs Plex at the highest resolutions without complaint, and is successfully (if slowly) backing up its shares to a commercial cloud provider using encrypted files.

So far I’ll call this an outstanding purchase, and I’m tempted to buy another.

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