[dba-Tech] SSD Diagnoser

[Rocky Smolin]

Thanks for that, John.  Good info.  I'll stop looking. :)

R


-----Original Message-----
From: dba-Tech [mailto:dba-tech-bounces at databaseadvisors.com] On Behalf Of
John Colby
Sent: Tuesday, September 06, 2016 4:26 PM
To: Discussion of Hardware and Software issues; jwcolby at gmail.com
Subject: Re: [dba-Tech] SSD Diagnoser

I have heard (can't swear to it) that even if there is a bad spot, the SSD
internal controller will find it before it is completely non-functional,
then move the data and mark the spot (sectors) bad.

So if you have a completely full (or very near full) drive, you may
eventually have a real problem.  If not, then the unused areas will be used
to hold the moved data if necessary.  I have also read that the SSDs have
"wear leveling" algorithms which will spread the writes around.  Only writes
are damaging to the SSDs.

If you think about it, any given cell can be written to about 2000 times.
Most of a drive is used to store files.  Most files are written once and
then sit there (unmoving) for the next 10 years. There are specific areas
that get changed a lot (think an MDB file, or a swap
file) but they are really few and far between.

One thing you do not want to do is run a defragger though.  Why? The SSD
does not have to move heads so it is (almost) as fast to read fragments
spread all over hell as it is to read a nice linear file.  And... the
defragger reads that file that otherwise would not move for the next 10
years and moves it intentionally to try and get it in fewer fragments.  
So the defragger causes wear that meant nothing in a rotating disk but which
means a lot (or more anyway) in an SSD.

I can tell you that I have used SSDs in a raid 6 controller with active
database usage for many MANY years and never had an issue.

As to your question, I have never seen a program which will "show you" 
wear happening on the SSD.

On 9/6/2016 10:51 AM, Rocky Smolin wrote:
> Dear List:
>
>   
>
> I upgraded my comp to an SSD about a year ago.  I've hears that they 
> don't last forever and develop bad spots over time. I'm curious to 
> know how this one is doing and to have a tool to monitor it from time to
tie.
>
>   
>
> Any recommendations?
>
>   
>
> MTIA
>
>   
>
>   
>
> Rocky Smolin
>
> Beach Access Software
>
> 760-683-5777
>
>   <http://www.bchacc.com> www.bchacc.com
>
>   <http://www.e-z-mrp.com> www.e-z-mrp.com
>
> Skype: rocky.smolin
>
>   
>
>   
>
> _______________________________________________
> dba-Tech mailing list
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> Website: http://www.databaseadvisors.com .
>

--
John W. Colby

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