Cheap drives (I use Crucial, AMD Radeon and Kingston) accept 3.000
rewrites per memory block. There are a few of interesting attributes you
can check from SMART. These are from my laptop (Crucial_CT960M500SSD1)
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE
UPDATED WHEN_FAILED RAW_VALUE
9 Power_On_Hours 0x0032 100 100 000 Old_age
Always - 8611
12 Power_Cycle_Count 0x0032 100 100 000 Old_age
Always - 4800
173 Ave_Block-Erase_Count 0x0032 096 096 000 Old_age
Always - 134
180 Unused_Reserve_NAND_Blk 0x0033 000 000 000 Pre-fail
Always - 16523
202 Percent_Lifetime_Used 0x0031 096 096 000 Pre-fail
Offline - 4
206 Write_Error_Rate 0x000e 100 100 000 Old_age
Always - 0
210 Success_RAIN_Recov_Cnt 0x0032 100 100 000 Old_age
Always - 0
246 Total_Host_Sector_Write 0x0032 100 100 --- Old_age
Always - 19329755627
247 Host_Program_Page_Count 0x0032 100 100 --- Old_age
Always - 616802682
248 Bckgnd_Program_Page_Cnt 0x0032 100 100 --- Old_age
Always - 3344366909
Attribute 173 states that, on average, each block was erased 134 times,
and states that it is about 4% of the liftime of the drive (attribute
202) was used. Check those/similar values on your drive. 4% on 8.611hs
suggests that I can continue to use the drive another 23 more years.
A few things you should consider:
* There is no wear from reading
* You should have as much free space as possible in order to level the
wearing. If your filesystem is pretty much full, all the
wear-leveing will occur on those few blocks that are released and
re-used. If you only have one block left, you will kill it in 3000
writes :-)
* Your filesystem shouls be aware that it is running on SSD in order
to mark blocks as free (so the SSD can do it's magic). I finally
dropped reiserfs for this reason.
* lot more things to consider, but these are the most relevant IMHO
* YMMV
Would you like to share your counters? Filesystem? application?
regards
ariel
El 22/07/18 a las 04:02, Jonathan Engwall escribió:
Does 345 power_on_hours seem like "old age"
Not happy. Thanks for the CEPH tip.
On Sat, Jul 21, 2018, 11:30 PM Jonathan Engwall
<engwalljonathanther...@gmail.com
<mailto:engwalljonathanther...@gmail.com>> wrote:
I built up a couple r610 dells with the idea that they would boot
from ssd through a usb external drive. The cheap external drives
might be the real culprits. I have to think about that.
The latest drive to fail was a Kingston and I think it was new.
There is a write limit on some ssds?
Lately I have been building trying to crosscompile the cray xmp
simulator. It has thousands of targets. But earlier this week
afterI installed openvswitch was when the trouble began.
Jonathan Engwall
On Sat, Jul 21, 2018, 10:44 PM John Hearns via Beowulf
<beowulf@beowulf.org <mailto:beowulf@beowulf.org>> wrote:
I forgot the main purpose of the Internet. My bad.
>You don't say for which purpose the SSDs are being used.
Storing cat pics?
On 22 July 2018 at 07:41, John Hearns <hear...@googlemail.com
<mailto:hear...@googlemail.com>> wrote:
You don't say for which purpose the SSDs are being used.
In your laptop?
As system disks in HPC compute nodes?
Journalling drives in a parallel filesystem?
Data storage drives in a parallel filesystem?
Over on the CEPH mailing list there are regular topics on
choice of SSDs. I would advise going over there and asking
the same question.
Also you don't say how they are failing.
Are these consumer grade drives or data centre grade drives?
Consumer drives have much, much lower 'drive writes per day'
Two jobs ago I would have said the go-to data centre
drives were Intel.
Also one comment specific to HPC. I found that SSD drives
dont 'get sick' like spinning drives,
ie you dont see syslog messages about blocks failing to be
read/written. They just fail.
Also two jobs ago I though that SMART checks were not
picking up failing SSDs.
I believe that you can monitor them if you choose the
correct counters. Anyone?
On 22 July 2018 at 07:32, Jonathan Aquilina
<jaquil...@eagleeyet.net <mailto:jaquil...@eagleeyet.net>>
wrote:
What Ones are you currently getting?
Sent from my iPhone
> On 22 Jul 2018, at 05:42, Jonathan Engwall
<engwalljonathanther...@gmail.com
<mailto:engwalljonathanther...@gmail.com>> wrote:
>
> I am not happy with the SSDs I am using. I am buying
another sad every couple weeks.
> Fast sure, but my productivity right now is zero.
> Are there any recommendations on reliable ssd brands?
> Jonathan Engwall
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