WD Red Pro Review: 4 TB Drives for NAS Systems Benchmarked
by Ganesh T S on August 8, 2014 9:00 AM ESTRAID-5 Benchmarking - Miscellaneous Aspects
Consumers are rightly worried about RAID rebuilds and the scope for drive failures during that process. As one of our evaluation aspects, we randomly yanked out a disk during operation and cleaned it up for rebuild. The graphs below show the resync durations (time taken to rebuild a 3-disk RAID-5 volume when one of the disks needs to be replaced) as well as the average power consumption during the resync process.
As expected, the low RPM drives tend to take a long time to complete the process. On the other hand, they also have the lowest power consumption during the process.
We also measured power consumption during the last stage of our multi-client test. With 25 different clients simultaneously stressing the NAS with different types of workloads, we recorded the power consumption at the wall for the NAS as a whole. The various numbers are presented in the graphs below.
As expected, the units providing better performance have higher power consumption numbers.
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willis936 - Friday, August 8, 2014 - link
Thank you for the overview of ATA protocol features on page 3. Resources like that are hard to find without spending hours digging through a spec.Anonymous Blowhard - Friday, August 8, 2014 - link
"Enterprise" or not, running RAID5 on 4TB drives with a 10^14 URE is asking for trouble.Guspaz - Friday, August 8, 2014 - link
Only when rebuilding. The chances of getting a read error on two disks at the same time on the same piece of data is extremely remote. Of course, when rebuilding, you only need the error on one disk... which is why I'm running raidz2 :)rufuselder - Thursday, October 9, 2014 - link
I'd say WD AV-GP 2 TB AV is the best choice (supported by for example http://www.consumertop.com/best-computer-storage-g... ). I'm not a big fan of raidz2, sorry.NonSequitor - Friday, August 8, 2014 - link
This came up on the last article about these drives as well. Currently I'm running six 3TB Reds in a RAID-6. Over the last year they've rebuilt once a month. I have Linux set to log any errors, and it's never logged a single block error. With the double parity, it seems like it would have logged one by now if the actual URE were that high on a per-bit basis. This unit was a replacement for a unit using nine drives, which did have two drive failures in three years, but both failures were announced by SMART before any actual failure occurred. The SANs at work do scrubs once a week, and kick out about 2% of drives a year. It really seems like reality is better than the specifications in this case.jaden24 - Friday, August 8, 2014 - link
Why are they rebuilding once a month?NonSequitor - Friday, August 8, 2014 - link
I have it set that way to spot a failing drive before it actually needs to be rebuilt. It's an orderly rebuild, checkarray, like this: http://www.thomas-krenn.com/en/wiki/Mdadm_checkarr...In the past it has been useful as it has caused drives to throw a SMART error for reallocates during the process (with some 1TB drives) allowing me to replace them proactively.
jaden24 - Saturday, August 9, 2014 - link
Interesting. I had never heard of the practice before. Only consistent scrubbing, SMART configured, and extended burn-ins prior to use.imaheadcase - Friday, August 8, 2014 - link
Ganesh, could you get a response from Synology/asus/Qnap/etc as to why they don't have NAS with better CPU/RAM? Those products are nice, but many people wish to have them with more CPU/ram for media streaming. I find it very odd than none of the major players don't contribute to this market.Why no 3ghz CPU and 16gig systems? It can't be cost since the ones that can be upgraded ram wise are cheap upgrades.
Out of the current popular NAS, only 2 support Transcoding, and multiple 1080p streams. But they have terrible software.
Gigaplex - Monday, August 11, 2014 - link
You don't need a 3GHz CPU, 16GB RAM NAS to support media streaming.