[geeks] Disks: recommendations?

[Lionel Peterson]

"Unlimited" equals 5 years?

Now they are talking about 20TB drives soon...

Ken (Lionel)

> On Oct 30, 2020, at 18:08, Joshua Snyder <josh at imagestream.com> wrote:
>
> o;?On 10/30/2020 11:02 AM, Jonathan Patschke wrote:
>> The seemingly-accelerated wear rate of moderns SSDs is exaggerated by how
>> fast they are.B  In active use, an SSD under an extreme write-heavy load
>> will fail faster than a mechanical disk in terms of calendar time, but
>> generally not in terms of blocks written.
>
> I remember seeing a Enterprise 15TB SSD that it's big claim to fame was it
didn't have any write endurance "limitations". It only had a SATA interface so
it was limited to ~600MB/sec interface speeds. Given the large size + the SATA
interface and the 5 year warranty it was impossible to burn-up the drive while
it was under warranty. So... marketing gave it "unlimited write endurance"!
>
>> I think I've seen three device failures out of several hundred in two
>> years.B  SSDs (from Micron/Crucial, Intel, WDC/SanDisk, and Samsung,
>> anyway) are astoundingly durable.B  Remember to issue discard/dsm (a.k.a.
>> "trim") commands for the unused portions of the media, and they'll last
>> ages.
>> There are lots of low-end players in the SSD space (Adata, PNY, etc.), and
>> my experience with those drives is that they are about as reliable as
>> cheap thumbdrives.B  Do not trust them for data you care about.
>
> I would agree that quality SSD's tend to be very durable. Early on there
were some low-end players that I know had issues. I know people that had total
drive failures with OCZ SSD's from the 2012'ish time frame.
>
> Getting back to the original question. I have an Intel X-25 160GB SSD I
bought in 2009. It's still going strong (73% life left currently). At one
point this drive sat unused for about 3 years. All the data on the drive was
totally fine.
>
> Most of the wear on this drive came when I used it as a Zil and L2Arc for a
ZFS file system.
>
>>> Do SSDs fail similarly, or do they just cross a line and go from
>>> "working fine" to "completely dead" when their firmware decides it's had
>>> enough?
>> SSD failure modes are manufacturer-dependent, but, generally speaking, the
>> failures are either media, controller, or DRAM.B  Media failure manifest
in
>> stuck bits or a whole lost page (64MB or so at a time).B  DRAM failures
>> manifest as unreliable transports.B  Controller failures manifest as a
dead
>> drive.
>>> I would hope they'd instead flip from "working fine" to "read-only", but
>>> I have little faith such hopes would be realized.
>
> I have seen both failure modes, drive is suddenly read-only and with the OCZ
drives I talked about, they just stopped working entirely. They didn't even
show up as drives when connected to systems.
>
>            Josh
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