[Tfug] Small-ish (capacity + size) disk alternatives

[Bexley Hall]

Hi Nick,

On 1/30/2013 5:41 PM, Nick Lopez wrote:
> On Jan 30, 2013, at 12:25 AM, Bexley Hall<bexley401 at yahoo.com>  wrote:
>
>>> [1]
>>> http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm
>
> So what I gather from this link is if you set out to make a custom
> program to try and destroy a small MLC SSD by constantly writing
> random data. you can succeed in two months of 24/7 abuse.

The problem is that you, the programmer, have very little control
over where and when data gets written to the medium in "big OS's"
(esp with large software components that you may not have a *clue*
as to the intricacies of their designs, etc.)

E.g., John's mention of "685TB of data to a 40GB (drive)" as if that
was admirable.  Yet, that's just ~15,000 times the capacity of the
drive (suggesting each FLASH block is rated at ~15,000 erase cycles).

Said another way, if you had 39GB of "executables" (i.e., data that
is never altered) on the drive, you might be limited to writing
ONLY ~15,000GB over the *life* of the drive.  An application that
wrote to the disk at 15MB/s would kill the drive in ~2 weeks! (!!)

(similarly, assuming you could write to the *entire* media "at will",
you're looking at 80 weeks).

> One of the big tech review / forum sites (Tom's Hardware, Anandtech
> sort) did a real world test as part of a data center migration and
> found that in the database server for the forums they're updates
> would burn out a single consumer grade SSD in 6-9 months. I wish
> I could find the article again.

Again, that tells you nothing about how this relates to some *other*
application (running different software, different customers, etc.).
All it demonstrates is that an SSD can have a VERY short life
IN PRACTICE.

> I suspect you're greatly overestimating your abusiveness, and

<grin>  No, I suspect it will turn out to be far worse when
everything is completed.  I.e., there is only *one* such device
shared by the entire system.  Every time you play some music,
watch video, run the washing machine, water your yard, turn on
a light, open the garage door, move from one room to the next,
etc. processes are updating the system's "state" on that medium.
(which requires more than just twiddling a few "bits")

> under-estimating the SSD controller's efforts to mitigate the
> abuse. This is just on the cheap $1/GB consumer drives, the
> enterprise SSDs with SLC or eMLC flash are rated for significantly
> more and are still way cheaper than RAM.

Would you want (TO PAY FOR) an enterprise class device in your DVR?

<grin>

I can use gold plated wire for all the connections, too!  But
I doubt many folks would want to duplicate my efforts if the
design relied on those sorts of "solutions".

I'll need to come up with an "unusual" solution.  Sort of like using
dog slow disk drives in iPods, etc.  I just don't want to get stuck
*manufacturing* anything!  :<

--don