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6 Terabyte Hard Drive Round-Up: WD Red, WD Green and Seagate Enterprise 6TB
MojoKid writes The hard drive market has become a lot less sexy in the past few years thanks to SSDs. What we used to consider "fast" for a hard drive is relatively slow compared to even the cheapest of today's solid state drives. But there are two areas where hard drives still rule the roost, and that's overall capacity and cost per gigabyte. Since most of us still need a hard drive for bulk storage, the question naturally becomes, "how big of a drive do you need?" For a while, 4TB drives were the top end of what was available in the market but recently Seagate, HGST, and Western Digital announced breakthroughs in areal density and other technologies, that enabled the advent of the 6 Terabyte hard drive. This round-up looks at three offerings in the market currently, with a WD Red 6TB drive, WD Green and a Seagate 6TB Enterprise class model. Though the WD drives only sport a 5400RPM spindle speed, due to their increased areal density of 1TB platters, they're still able to put up respectable performance. Though the Seagate Enterprise Capacity 6TB (also known as the Constellation ES series) drive offers the best performance at 7200 RPM, it comes at nearly a $200 price premium. Still, at anywhere from .04 to .07 per GiB, you can't beat the bulk storage value of these new high capacity 6TB HDDs.
On a 4-bay NAS box, there aren't enough slots to have a SSD acting as a cache unless you want to give up one of your very valuable bays.
If you want to avoid problems with FS failures and accidental deletions, then you can go without RAID and just sync the discs every night. This is what I do on my home desktop and it works just fine. At worst, I'll lose a day's worth of data, which wouldn't be the end of the world. I think that 3 drives with 2 in mirrored RAID and 1 running a nightly backup would be ideal. You could lose a drive and not lose any data, and any kind of file system errors or accidental deletions could also be easily dealt with.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
There are some useful bits in the blog post by Backblaze, as they care a lot about making a good choice between the two 6TB drives.
Once the electrons are out of the gate, the data is -gone-. No amount of recovery is going to do the job, ever.
This is my biggest concern with SSDs. Yes, they can have a longer MTBF, but when they go, they take your data with it, making backups more imperative.
The ironic thing? Since SSDs make the need for backups that much more urgent [1] We have far fewer tools for backup than we did on PCs 20 years ago (when an average user could get a desktop tape drive, a ZIP drive, removable SCSI hard disk, or other media.) For non-enterprise backups, we have external hard disks, USB flash drives, and offsite file servers [2]. Even optical drives are becoming uncommon. External hard disks and USB flash drives are not archival media. They -might- hold their data, but are not warrantied for it.
It would be nice if some company could make an appliance that did a disk-to-disk-to-removable-media appliance. The backup program would copy data to the device, and data would stay on a set of RAID protected HDDs, as well as eventually copied to removable media [3]. A bare metal restore would be easy -- if the appliance is connected via USB, have it present a DVD-ROM with the OS or recovery software. If on a LAN, have a USB flash drive or image that would get a machine booted enough to find the appliance and start a restore.
[1]: With HDDs, a recovery from a format isn't too difficult. SSDs usually follow up a format with a TRIM command, zeroing (or more exactly, writing 1s) to all the blocks, either right then, or as the drive feels like it. "Unformatting" a SSD is pretty much impossible with a modern OS that does proper TRIM commands. Add a decently smart encryption system like BitLocker that zeroes out the sectors with master volume keys multiple times, and it can almost be assured that a delete or a format results in data forever gone.
[2]: Cloud storage seems like a working idea, but it can take a good while to fetch lost documents and rebuild the entire OS and machine. With a local backup solution, most backup programs offer a simple bare-metal restore, no Internet access needed. There is also the fact that a machine needs to have the OS, updates, and the cloud provider's software loaded and logged in before a restore can happen. Having the OS local means a complete bare metal restore is a "press 'restore' and walk off" action.
[3]: Tape comes to mind. The main advantage of tape (or offline media in general) is that some hacker who gets access to the SAN controller can't just purge all media with a single command. A lot of companies have excellent replication of SAN data, but that replication will happily replicate the "delete everything, including all snapshots" as well. Plus, tapes can be physically set read-only where only a reflash of the tape drive could allow the cartridge to be written to. I wish someone could make a consumer level tape drive, perhaps using a SSD as a buffer to prevent shoe-shining. There is a Thunderbolt based tape drive for Macs by mTape for $3699. If someone made a product like this (but a price more palatable to consumers) that could tolerate USB 3 (or maybe even USB 2), and work well under Windows, Linux, and other operating systems, they might have a best seller. Especially with the fact that intruders now have moved from just accessing data to actively modifying and destroying it, so backups are even more crucial than they were before this year.
In fact, I'd say that with the ease data is permanently destroyed, a consumer level backup appliance might be quite a seller.
BINGO
The underlying issues with flash can be and are successfully hidden by the controllers in modern SSDs for most workloads (very heavy write loads can be problematic) but that hiding comes at a price. The firmware in a SSD is far more complex than an a HDD and so for a given level of engineering effort it will be less reliable. In particular i've noticed corruption after unclean shutdown to a far greater extent on SSDs than HDDs.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register