Largest Hard Drive Available vs. RAID

Factual Questions
21

I participated in a thread at http://www.videohelp.com about a similar question. My suggestions there apply here.

Stay away from drives in an external case* from Seagate and WD because the cases are cheap (external drives sell for less than internals because the the cases are cheap) and are prone to the USB connection dying prematurely.

External drives in LaCie, Fantom and a few others are fine since they’re premium cases with internal drives.

*If you’re willing to open the case and possibly void the warranty (which can be as little a one year anyway) to remove the drive (which are identical to those sold separately) to use as an internal, they are the greatest bargains currently available. More about this below.

Unless you really need the spanning and redundancy of Raid, get a multi-drive external HDD enclosure like a Mediasonic Probox which are available in 4 & 8 bay configurations that have USB 3.0 and eSata connections with RAID capability for a bit more. They’re definitely compatible with 10TB drives (I have a couple of 10TB drives in mine) and there’s no reason they wouldn’t work with larger drives also.

Note that all prices are U.S. as of May 2018

I have 10’s of TBs of HHDs and buy new drives based on price per TB with Seagate and WD 8TB external drives (that you’ll remove the drives from ) are the sweet spot for price per TB @ ~$20/TB (<$160 per drive). 8TB & 10TB internal drives are ~$30/TB and 12TB drives are ~$35/TB

A 4 bay Mediasonic Probox is ~$100 and the 8 bay model $250 (I have both) and they work identically.

For <$1000, you can get five 8TB externals (40TB storage) + a 4 bay Probox or three 10TB internal (30TB storage) + a 4 bay Probox that you can swap drives in and out of.

You state your files are ~4TB, so if they’re 4TB or less, you can store two files on an 8TB drive. If they’re between 4 and 5TB, go with the 10TB drives.

I’m not sure if this still applies, but the real bargain through the end of last year was that all WD 8TB externals contained WD Red NAS drives that retailed as internals for twice the price. Yes, you risk voiding the warranty by opening the case (that is extremely easy to do without breaking any tabs), but you get a high quality drive for half the price. Knock wood I haven’t had to do this yet, but I’ve read that WD may honor the warranty on an opened external drive (replace the drive back into the case) since the warranty is is on the drive itself, not the case/drive combo.

22

Another option if you are on a PC and not on a Mac (which I understand no longer have any externally accessible drive bays) is to use removable drive cages. Some will allow up to four 3 1/2" HDDs by using three 5 1/4" external bays. The advantage over external USB 3.0 drives is the faster read/write speed offered by SATA (eSATA on external cases offer the same advantage), though I find for my purposes USB 3.0 is nearly as quick.

If you motherboard supports it, you could run the drives in a RAID configuration. If your board doesn’t support RAID, you can use an add-on card.

23

Windows has supported Dynamic Disks and spanning to make multiple drives appear as one since Windows 2000. There’s redundancy, but I prefer method md2000 suggested, manually copying data from one drive to the other.

The major advantage to RAID 1 or RAID 1+0 is drive mirroring which removes the time required to move multiple TBs of data from one drive to another which takes hours (~12-14 hours via USB 3.0 to USB 3.0 for 8TB in my case where there are multiple “small” multiple GB files. Larger files transfer quicker).

24

Those are Thunderbolt 2, not usb.
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25

Isn’t there some way to take advantage of multiple drives not just for more space for data, but for higher sustained transfer rates? If one drive operates at, say, 300 megabytes/s, then writing 4 TB will take nearly 4 hours. Writing that in parallel across 4 drives would take less than an hour.

As for software versus hardware RAID, is that a bottleneck limiting read/write speed, or will it be the drive itself?

26

I am also thinking, even with error rates at 10[sup]-15[/sup], you still want to turn data checksumming on to mitigate the effect of flipped or lost bits.

27

Oops! :eek: Good catch! :slight_smile:

28

Interesting and helpful advice. The only thing I would note is that external drives often don’t advertise their size (3.5" or 2.5") and RPM (7600 vs. 540). So you might have to do a digging, and make sure you compare them to the internal drive with the same specs.

29

Phew…moving a 4TB file over USB would be painfully slow (close to 24 hours to move that one file over USB). Thunderbolt can do that in 20-30 minutes.

30

Thunderbolt 2 is about 2x faster than USB 3.1, no?

31

Yep. 20Gbps.
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32

My thoughts:

USB 3.0 and beyond, USB 3.1, USB-C, Thunderbolt speeds are all far beyond the limits of mechanical hard drives which top out at ~160MB/s (~1.3 Gb/s) which is far below even SATA II (3 Gb/s).

Good point about 5400 vs 7200 RPM drives. I use my drives primarily for storage so don’t worry about drive speed, but it’s safe to assume most external drives are likely slower 5400 RPM. AFAIK, all non-portable externals contain 3.5" drives, especially since 2.5" drives are more expensive.

I’ve gone through dozens of large 3TB+ drives over the years and the only one in my experience to avoid if you want performance is the 8TB Seagate Archive Drive which as it’s name states, is slow when writing files (read speeds are in line with your typical 5400 RPM drive.

I’ve been following Backblaze’s reports for years and while they’re very informative, they must be taken with a large grain of salt. The author states that the drives are subjected to stress such as 24/7 usage, heat and vibration that wouldn’t occur in any home environment.