28 Aug
2020
28 Aug
'20
1:36 p.m.
On Aug 28, 2020, at 1:40 PM, Al Kossow via cctalk
<cctalk at classiccmp.org> wrote:
On 8/28/20 10:10 AM, Paul Koning via cctalk wrote:
Yes, if they wear out. But the lowest I have seen is around 100 writes per sector, which
means that once you've written 100x the device capacity total (times the "write
amplification" which depends on write size patterns) you'd start to consume spare
sectors, and you don't have a problem until those run out which is still some time
later.
That said, I have seen it happen, with very small CF cards and software that was, by a
coding slip-up, writing every few minutes non-stop.
SD is a packet based storage device on a serial
interconnect
You really do need SMART monitoring on solid-state storage
which may or may not exist in the adapters. SSDs will silently
fail if they run out of sectors to write to. Also, I discovered recently that there is a maximum
number of hours
measured in years on SSDs and systems will start throwing SMART
errors when that is exceeded. I have a few doing that now on systems
with minimal writes but lots of hours.
That's curious. There may be a read retention time limit, though I think that applies
only if the device is powered down. When powered up, the device firmware takes care of
refreshing the sectors, somewhat like memory refresh but with refresh cycles of weeks or
months.
There are long discussions elsewhere of the dangers of
using non-industrial
rated CFs and SDs in storage applications.
Good advice for serious work especially if you're running heavy workloads. I
wouldn't worry about it much for my home firewall. But the servers running
bitsavers.org are an entirely different matter.
One way to look at it: if you are, or should be, using RAID, you should be using
industrial grade SSDs.
paul