Is there a program that can interrogate a flash storage device to
determine how many spare blocks remain?
I'm looking for a way to guesstimate when it's time to replace a
microSD card or USB flash drive before it fails completely.
Thanks for reading,
On Tue, 2 Oct 2018 01:44:07 +0000 (UTC), bob prohaska
declaimed the following:
It's probably meaningless -- since it depends upon how the internal
controller was programmed. A device might be programmed with NO reserve
blocks -- all blocks are considered usable from the beginning, whereas a
similar device might have been programmed to reserve 5% of the total space
for "bad block remapping".
Of course, since SD card wear-leveling algorithms mean data moves
around every time one writes to a block, remapping takes place all the
time... A card that reserved space could actually have blocks go bad sooner
than one that didn't -- as the one that didn't is distributing the wear
over all the blocks, rather than waiting for a block to fail before making
use of any blocks in the reserve area.
What will kill a card is having a large proportion filled with
relatively static data, and only a small amount of dynamic (log files, say)
data -- as the dynamic data will keep recycling (erasing for reuse, then
writing) the same small set of blocks over and over, wearing them out while
the static data sits happily in blocks with a capability for high reuse. A
card with "all" dynamic data will tend to reuse all the blocks through wear
Wulfraed Dennis Lee Bieber AF6VN
I didn't realize the Pi supported badblocks. I'll give it a try.
My predicament was revealed by fsck: a fault was found, fsck asked
permission to fix the fault and told me to run fsck again. The fault
was still present. This went on till I gave up. If the block with the
error is bad, and there are no spare blocks to replace it, this makes
good if unhappy sense. I'm looking for some measuring tool that looks
past the flash controller to independently ascertain the state of the
Thank you very much!
You don't get that in cheap SD card flash designed to temporarily store
photos and to be obsolete before it reaches its wear life.
You need to use something that is designed to be primary computer
storage, i.e. an SSD, as it's controller will not only be better at wear
levelling, but also support all the health monitoring information.
I think this boils down to not using SD cards designed for capturing
streaming data, i.e. for use in a video recorder (type codes 10,
30,60,90) for random access use, such as supporting a Linux filesystem.
I've just ordered a Samsung Evo + 128GB microSD card, basically as an
experiment. It'll be close to twice the capacity I need, maybe that'll
help the working life. It claims a uhs3 speed rating, but I'll believe
that when the package arrives.
The 16 GB card that failed actually lasted a rather long time; about
six months of continual compiling, finally run up to over 90% capacity
at the time it quit. In my environment that's probably an order of
magnitude more writing than will happen in real use.
Is there any chance re-partitioning the failed device might wring a little
more life out of it? Badblocks reports all bad blocks, but I was able to
write a small file on the DOS partition, so it's not totally stuffed.
Thanks to everyone for reading and posting.
On a sunny day (Thu, 4 Oct 2018 01:18:18 +0000 (UTC)) it happened bob prohaska
wrote in :
Just an idea, if you use extra partitions on such a big card,
then make sure you mount those with the 'noatime' option.
That significally reduces write cycles to the card:
When used for large file operations with a USB3 card reader, it will be
very quick. As its a Samsung it will have OK performance with the
Raspberry Pi, but no faster than any other class 10 card, and probably
not as good as an older Samsung class 4 or 6.
The 128GB card will last longer a bit longer, but its not the best
solution. A 128GB SSD would last for just about ever, and be vastly
quicker for random access operations, particularly compiling.
The only reason not to get it would be lack of space for an external
drive, in which case a Samsung USB3 bar would give almost the same
performance as an SSD from the Pi, and much better life than an SD card.
Once its found to be unreliable, bin it. Anything else is just inviting
Small capacity SSDs (SD card sized) are quite cheap, you can even pick
up used ones on ebay which have plenty of life left in them. As for
power, SSDs don't get as hot as some SD cards or USB sticks, the smaller
ones can get too hot to touch when used in a Pi.
10-05-18 09:17 Anssi Saari wrote to email@example.com about Re: Software to
Howdy! Anssi Saari and ALL,
AS> firstname.lastname@example.org writes:
AS> Yes. One might consider an SSD in a USB enclosure to have that
AS> information. I recently built one for myself, just as a fast portable
AS> media. Enclosure from ebay and drive (M.2 2240 size) from a local
AS> Price was about the same as a fast USB stick (128 GB) but you get
AS> support for TRIM at least. I haven't checked SMART, support really
AS> depends on whether the USB controller passes through those commands
AS> through to the driver or not.
AS> Physical size is somewhat wider and longer than your typical USB
AS> stick. The width causes trouble with tightly grouped USB ports. There
AS> might be better enclosures than what I got.
A USB 2.0 cable with USB A connector on one end and the other end has a
USB B connector may be helpful.
Getting a B-I-G USB enclosure (or Thumbdrive) plugged in to something
like a USB Hub where the slots are close together can be very trying...
Instead of buying Thumbdrives, I've been buying Micro SD cards.
I slip them in a SD card Adapter and insert that into a SD card to USB 2
And Yes!, I use the USB A to B cable when I need to use it.
The SD card Adapter has a Lock lever whereas Thumbdrives don't have one.
I 'think' that that lever keeps the (Micro) SD Card from getting anything
written to it unless I move the lever to allow something to be written to
I feel safer having the lever in the Lock position when I use it in My
computer OR with a friends computer.
I Scan the card with Avast, Malwarebytes and SuperAntiSpyware Before I go
to use it in a friends PC, and Scan it again After I return home.
I don't want the card to put MALWARE on a PC, especially not on mine.
Practicing Safe Computing makes one PARANOID doesn't it?
... !uoy knaht ,enif tsuj gniod m'I
The Samsung Portable SSD T5, 250 GB version for ?90 is definitely a better
price per GB and probably a better product if you don't care about the
stick form factor. For one it's actually usb 3.1 gen2, not 3.1 gen1 which
is actually just 3.0; although of course one or the other won't matter with
the RPi's usb 2.0 ports. More importantly, and it's maddening that they
don't give technical details, I trust the controller/provisioning of an
actual ssd in external housing more than a "solid state" usb stick.
But yeah, at ?90 it does get a bit mad for a $35 computer. What I did for
my home server which has to be more reliable than an sd card, is buy a 2.5"
portable spinning disk of 1 TB for, idk, ?45? Speeds are fine over usb 2.0
and as a server on wifi. Haven't used it on the desktop, though; maybe it
would need more snap there.
Any idea what sort of power consumption can be expected for a
modern small mechanical hard drive? The only one I have is old
and probably uses twice the power of the Pi when idling. For 24/7
operation that does add up. The extra wallwart and wires don't help.
Thanks for writing!