Mailinglist Archive: opensuse (686 mails)

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Re: [opensuse] SSD and smartctl: Percentage Used Endurance Indicator: 34 ?
Am 07/07/13 04:00, schrieb Rajko:
On Sat, 06 Jul 2013 12:48:42 +0200
MarkusGMX <Markus.Egg@xxxxxx> wrote:

...
(rev 1) == 7 0x008 1 34~ Percentage Used Endurance
...
manpage says:
"ssd - [SCSI] prints the Solid State Media percentage used endurance
indicator. A value of 0 indicates as new condition while 100
indicates the device is at the end of its lifetime as
projected by the manufacturer. The value may reach 255."

How accurate is this?

Note "projected by the manufacturer" is not defined in any way that
will tell us how to understand that 34%. Although:

http://www.crucial.com/pdf/Tech_specs-letter_Crucial_m4_ssd_v3-11-11_online.pdf

tells that 128GB model has 72TB endurance, which translates to 40GB
per day during 5 years. In other words if smartctl reads data correctly
then you used in last 2 years 24.5 TB writes, or 33.5 GB per day (730
days) which from where I stand can be called a heavy usage.

Hmm, 33.5GB per day cannot be possible.
The whole /var has only ~18GB which would mean writing the complete /var approx. twice per day, which surely does not happen.
;-)
swap is probably also written more often but most of the time it seems to be not
used as top says
Swap: 32655M total, 0M used, 32655M free, 6718M cached
(with 16GB Memory).

/boot is not a problem imho.
So either www.crucial.com is wrong or smartctl.
Or both.
:-)

[...]
... ~6 years is that the normal lifespan of SSDs nowadays?

It can be even shorter with heavier usage.

With my usage it will be more likely that smartctl reads something
wrong, or something is happening that should not, crating such high
number of erase/writes cycles.

If smartctl is correct...
33.5GB per day would be strange for /var and swap .

[...]
What you can do is to check your partition mount options. Other already
elaborated on that, but there is one that is probably missing -
"discard".

Check as root does your disk support TRIM:

hdparm -I /dev/sdX | grep -i TRIM

hdparm -I /dev/sda | grep -i TRIM
gives:
* Data Set Management TRIM supported (limit 8 blocks)
* Deterministic read data after TRIM


(X is a drive letter)

and if yes enable it with option "discard".

http://en.opensuse.org/SDB:SSD_discard_%28trim%29_support#Kernel_support

Complicated. It would be nice to have sections per SuSE release on this webpage:
e.g. one section for 12.1, one for 12.2., one for 12.3 ...

greg.freemyer@xxxxxxxxx wrote in another post that discard is not needed.

I had the opinion that SuSE 12.1 handles all that.
:-/
Is there some easy switch to enable SSD-optimization in yast2?
That would be the easiest way.
:-)

[...]
How to enable is another question:

https://en.opensuse.org/SDB:SSD_performance

Question is now: discard or fstrim ?


http://forums.fedoraforum.org/showthread.php?t=277082

which is pretty new, has a lot of advices, but may have some advices
that don't apply for newer computer with a lot of memory (about having
swap on classic disc).

I have a lot of RAM but even with that sometimes swapping is indicated and swapspace is also on this SSD.


Thanks to all
ME

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