Western Digital releases new 18TB, 20TB EAMR drives:
Earlier this month, Western Digital announced retail availability of its Gold 16TB and 18TB CMR drives, as well as an upcoming 20TB Ultrastar SMR drive. These nine-platter disks are the largest individual hard drives widely available today.
Earlier this year, rival drive vendor Seagate promised to deliver 18TB and 20TB drives in 2020, but they have not yet materialized in retail channels.
Seagate's largest drives, like Western Digital's, needed a new technology to overcome the Magnetic Recording Trilemma—but Western Digital's EAMR (Energy Assisted Magnetic Recording) is considerably less-exotic than the HAMR (Heat Assisted Magnetic Recording) used by Seagate. That more conservative approach likely helped Western Digital beat its rival to market.
The maximum usable data density on a magnetic recording device is limited by three competing factors. Magnetic coercivity—the strength of magnetic field required to demagnetize a domain—must be high enough to prevent the separately recorded grains from influencing one another and corrupting data. The field strength of the write head must be high enough to overcome the coercivity of the medium. Finally, the size of the field generated by the write head must be small enough so as not to overwrite adjacent areas.
[...] Although Western Digital is continuing its research into MAMR technology, the tech used in this month's new drives—EAMR, or Energy Assisted Magnetic Recording—is considerably less exotic. Rather than alter the magnetic properties of the medium with microwave or laser emissions, EAMR simply stabilizes the write field more rapidly and accurately, by using a bias current on the main pole of the write head as well as the current on the voice coils.
The potential data loss from drive failure grows ever larger...
Related Stories
Toshiba Unveils World's First FC-MAMR HDD: 18 TB, Helium Filled
Toshiba this week announced the industry's first hard drive featuring flux-control microwave-assisted magnetic recording (FC-MAMR) technology. The new MG09-series HDDs are designed primarily for nearline and enterprise applications, they offer an 18 TB capacity along with an ultra-low idle power consumption.
The Toshiba MG09-series 3.5-inch 18 TB HDD are based on the company's 3rd generation nine-platter helium sealed platform that features 18 heads with a microwave-emitting component which changes magnetic coercivity of the platters before writing data. The HD disks are made by Showa Denko K.K. (SDK), a long-time partner of Toshiba. Each aluminum platter is about 0.635 mm thick, it features an areal density of around 1.5 Tb/inch2 and can store up to 2 TB of data. The MG09 family also includes a 16 TB model which presumably features a lower number of platters (based on the same performance rating).
Previously:
Toshiba Will Adopt Western Digital's Microwave-Assisted Magnetic Recording Approach for Hard Drives
Toshiba Roadmap Includes Both MAMR and HAMR Hard Drives, as Well as TDMR and Shingles
Western Digital Releases New 18TB, 20TB EAMR Drives
(Score: 2, Interesting) by MIRV888 on Saturday July 18 2020, @06:23AM (2 children)
I just got 2 8TB usb drives to backup my media server. It took a couple days to copy the data over (4 4Tb on the server). I have lost drives in the past, and the stakes get higher and without backups.
(Score: 3, Insightful) by takyon on Saturday July 18 2020, @09:03AM (1 child)
The $/TB gap is still about 5:1 in favor of HDDs (according to my numbers). If that shrinks significantly, HDDs should die for consumers. If SSDs have a reliability advantage, you can probably stomach 2:1 or 3:1.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 4, Informative) by Booga1 on Saturday July 18 2020, @12:56PM
Cold storage could still be an issue with SSDs. My Sandisk SSD came with a warning that it only guaranteed data retention for up to one year without power. Unfortunately I never got to test that because we had a brown out after my UPS died and the rapid triple power cycle killed the SSD. The regular hard drives survived just fine...
(Score: 4, Informative) by Booga1 on Saturday July 18 2020, @07:40AM (6 children)
For the editors:
Is it possible to just not include Amazon(and other) affiliate links? I know it's not added maliciously or anything since it's in the original article. Still, it seems rather tacky to have links with the sole purpose of selling products and aren't informative in story submissions.
(Score: 4, Informative) by takyon on Saturday July 18 2020, @09:06AM (1 child)
Probably wasn't noticed. Now it's gone.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Informative) by martyb on Saturday July 18 2020, @06:27PM
Wit is intellect, dancing.
(Score: 4, Informative) by martyb on Saturday July 18 2020, @05:33PM (3 children)
Urk? Ooooops!
I despise affiliate (and tracking) links of any kind. We easily run into them every day or two in the story submissions we receive. I endeavor to remove them from all articles.
I've replaced the link that was in the story with a direct link to the item.
I apologize this one slipped though and thank you for mentioning it!
Wit is intellect, dancing.
(Score: 2) by Reziac on Sunday July 19 2020, @02:12AM (2 children)
Why not link to WD's site instead of Amazon? (first link)
Also, WD often has better direct-sale prices than anywhere else, and you can be sure you're not getting grey market and an iffy warranty. (*cough*Newegg*cough)
And there is no Alkibiades to come back and save us from ourselves.
(Score: 2) by martyb on Sunday July 19 2020, @03:37AM (1 child)
Wit is intellect, dancing.
(Score: 2) by Reziac on Sunday July 19 2020, @03:50AM
Ah, okay. No worries. :)
And there is no Alkibiades to come back and save us from ourselves.
(Score: 1, Touché) by Anonymous Coward on Saturday July 18 2020, @11:28AM
"Fuck you, consumers" says marketing whiz at WDC as he OK's switch to 18TB SMR drives.
(Score: 0) by Anonymous Coward on Saturday July 18 2020, @05:35PM (6 children)
"The potential data loss from drive failure grows ever larger..."
Buy a pair, and use RAID-1.
If you also want a backup, buy three, keep two in operation, periodically replace one with the third as a backup.
(Score: 1, Funny) by Anonymous Coward on Saturday July 18 2020, @09:50PM (1 child)
It's easier just to wait for drive failure and then replace all your valuable data with one command...
#cp /internet/*teens*.mkv /home/mydata/pr0n/
(Score: 1) by MIRV888 on Saturday July 18 2020, @10:24PM
lol
(Score: 2) by TheRaven on Sunday July 19 2020, @03:04PM (3 children)
sudo mod me up
(Score: 2) by sjames on Monday July 20 2020, @07:38PM (2 children)
That's one reason I've been looking at BTRFS with multiple disks. For example, given disks A,B, and C, to replace disk B, half of A gets copied and half of C. More disks spread the reading further.
Just don't configure RAID 5/6 in btrfs, that leads to tears.
(Score: 2) by TheRaven on Wednesday July 22 2020, @10:42AM (1 child)
So btrfs uses block-level mirroring? To handle any single-disk failure, that would sacrifice half of your capacity. If any given block has copies on either (A, B), (B, C) or (A, C) then all blocks take up double the space that a single copy would take. In a two-disk setting, this is equivalent to RAID-1. In a three-disk setting, it gives the same level of redundancy as RAID-5 (or though closer to RAID-Z): it can recover from any single disk failing. The cost is significantly higher in terms of storage overhead. RAID-5 or RAID-Z require one disk's extra space to handle single-disk failure whereas this approach would require half of the total pool size. The only benefit is reduced resilvering load (though given that most disks can read faster than they can write, I doubt it would make a performance difference: your pool is still degraded until you've written the entire replacement disk). To handle three-disk failure with this scheme, you'd need to use 2/3 of your total pool capacity for redundant storage, whereas with RAID-6 or RAID-Z2 you need to pay only two disks (so a 6-disk array with this scheme would have 2 disks useable capacity, RAID-Z2 or RAID-6 would have 4 disks useable capacity).
If this is really what btrfs is doing, I'm very surprised. From what I've seen, it does have a mode that is analogous to ZFS's 'copies=2' mode, but that is not intended to protect you against complete disk failure.
sudo mod me up
(Score: 2) by sjames on Wednesday July 22 2020, @12:13PM
BTRFS is doing the equivalent of RAID10. There are a great many conventional RAID10 arrays out there. One additional bit, in the case that a disk becomes unreliable but not totally dead, it's checksumming can determine which bits are still good.
Also since it is at the file level, the disks don't need to be of the same size or added in pairs.
Minor math correction, in the 6 disk array, it's capacity of 3 vs. capacity of 4.
Also, with RAID 6, you can lose 2 disks, if you lose a 3rd, you lose the array.
But given the way that drive capacity is growing, it's also nice that a btrfs system cab grow organically without leaving space unused. So, for example, you have a pair of 2TB drives. You can later add a single 4TB drive for a total of 3 disks and 4TB fully redundant storage.
BTRFS does have higher raid modes, but based on my testing, I wouldn't go anywhere near such a configuration until the bugs are out.