Yousuf Khan wrote:
So Seagate and other makers are getting ready to introduce 20 TB HDD's
to the market. According to Seagate, its fastest drives are capable of
sustained 250 MB/s transfers (if you believe them). It would take 30+
hours to entirely fill such a drive with data at maximum speed! Is that
too much time, no matter how much capacity you are getting? Is that
basically unusable capacity? I know you can say that a drive that large
would be filled over a number of years, and no one would be filling it
all up in one go.
But that's probably true in a home environment, but what about an
enterprise environment? What if that drive were part of a RAID array,
and one of those drives failed and needed to be replaced? In RAID
parity, the entire drive has to be written to, because the parity is
required on all drives at once. Imagine you start synchronizing a
replacement drive like that, and it takes 30 hours to do that? That's a
long enough time that it's conceivable another drive within that array
would fail too, before it's had a chance to completely resync with the
array. So sure, you can get that capacity with an HDD, but should you
really be storing your data on something that slow? HDD's can't get much
HDDs are not only used by consumers that have 1 to 4 units in their
computers. They are also used by datacenters that have THOUSANDS of at
their site, and then THOUSANDS more at other datacenters to provide for
catastrophic physical disaster (flood, tsunami, earthquake, meteor,
falling aircraft and space junk, terrorism, etc). Google has
datacenters in 13 locations: N. and S. Carolina, Iowa, Georgia,
Oklahoma, Oregon, Hong Kong, Singapore, Taiwan, Finland, Belgium,
Ireland, and Chile. Through subsidiaries, they have datacenters
elsewhere, too: Virginia, Alanta GA (multiple), Netherlands (2
locations), Hungary, and Poland,
"As of December 31, 2019, Backblaze had 124,956 spinning hard drives."
Ranked by square footage. The Citadel (www.switch.com/the-citadel
largest sized. It's hard to get them to concretely expose their total
storage capacity. The estimate for Google is 10 exabytes which, using
your 20TB HDD example, would consume 500,000 HDDs. At Google, an HDD
dies every few minutes due to the sheer number of drives they employ.
Just because YOU don't have that much data to retain or archive doesn't
mean no one else does. The average 4K movies consumes about 100GB.
Would only take 200 movies to fill up a 20TB drive. According AllFlicks
back in 2016, Netflix had 6,494 movies back then (and 1,609 TV shows).
While Netflix discards movies after awhile, I'm sure they've grown since
The more disks you have spinning, even when adding to a RAID config, the
more fragile becomes the setup. Putting the same amount of data on less
mechanicals means less chance of physical failure.