
SSD myths and legends: write endurance - wslh
http://www.storagesearch.com/ssdmyths-endurance.html
======
xkiwi
In the middle of reading this, I saw a 2TB SSD Advertisement then realized SSD
just consumable product, it is just like tires which just change it every 2-3
years, for safety concern.

~~~
kayoone
Thats the right way of thinking about it but its not really feasible for
consumers.

"Oh hey, this Laptop has a SSD drive which is super fast. You will have to
replace it every year though and if you dont have a backup strategy you might
lose all you data. Did i mention they are quite expensive ?"

~~~
venomsnake
You will have to make quite the effort to burn trough a consumer SSD in
machine with normal use for a year. 256 GB * 3000 gives a lot of write
information.

~~~
kayoone
In theory yes, in practice i have been using SSDs since 2009 and had them both
failing (different brands and tech) after about 2 years of daily usage. Now i
see i probably use them more than the average consumer, but i cant remember
the last time i had a normal HDD fail in one of my machines.

~~~
dchichkov
I've seen a number of normal HDD failures. I think that the first one that
I've seen, been with a double-5 inch slot hard drive, which was failing to
start spinning at times. You've had to turn the PC box abruptly, to make it
spin ;)

But as of now, have to see an SSD fail. Longest running that I have now is a
Linux box that've been up since Oct/2007\. (Heh, cool part about that linux
box - there are no moving parts at all - no coolers, no nothing. Even in the
power supply ;) )

~~~
kayoone
Sounds cool :) I am not saying i have never seen HDDs fail, but in the almost
20 years i have been computing heavily, it might have been about 3 in my own
machines, while i went through 2 SSDs in 4 years. Id still never go back to
HDDs as my system drive :)

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jmomo
For those in the know, and for the benefit of laymen who don't have the time
to do the research, what are the things that a buyer should look for in a SSD,
in regards to reliability and longevity? Technology, brand, controller?

~~~
andrewcooke
the only critical thing is physical size. some (mainly ultralight) laptops
take drives that are thinner than normal laptop drives (this is also an issue
if you're buying a new spinning disk drive, of course).

apart from that, assuming you buy a popular, current model, it will just work
(and be reliable). this article is bikeshedding for hardware and enterprise
geeks. so, just like anything else, get something reasonably priced from a
reputable make (longevity of support, availability). currently samsung seem
pretty good.

and finally, if you don't already use one, get one. it's by far the best way
to improve "perceived speed" of your computer (well, assuming you already have
enough memory).

~~~
mdpye
My Intel X?? came as a superslim 2.5 package, but with a plastic bumper as
part of the construction making it up to full height. Having to disassemble it
first thing to remove the buffer went just fine, but wasn't a great start
(warranty voided before I even powered it up?)

~~~
gcb0
Had to remove enclosure of a Kingston drive to fit a notebook also. Just
cycled all the storage in the desktop before voiding my warranty... Still
sucks

In your case it's double ironic since Intel is the one that pushed for slim
ssd because of the ultrabook shenanigans while everyone was doing a standard
size. Not that having smaller drivers is bad...

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ck2
Write endurance is very real.

[http://www.ssdaddict.com/ss/Endurance_cr_20130122.png](http://www.ssdaddict.com/ss/Endurance_cr_20130122.png)

[http://www.xtremesystems.org/forums/showthread.php?271063-SS...](http://www.xtremesystems.org/forums/showthread.php?271063-SSD-
Write-Endurance-25nm-Vs-34nm)

~~~
Shivetya
The data given on the second link does not inspire confidence in consumer SSDs

~~~
corresation
How so? The tests are in no way normal usage, most writing hundreds of
terabytes or more before failure, exactly in the expected range for those
sizes of SSDs.

Consumer devices do not write remotely as much as people seem to think they
do. Heck, I ran a very large, endless-churn financial system on a FusionIO
platform, and two years in it had barely written several hundred terabytes.

~~~
Shivetya
I was looking at SSDs as scratch disks and the like, but some of the examples
failed in months. Its an electronic device, sorry but other than purposely
putting in an environment that is not conducive to its long term health, like
heat or dunking it, I should be able to read and write to it to my heart's
content.

I fully understand commercial grade equipment versus consumer, but in the
world of no moving parts it begs the question, what does it take to make them
more reliable. Because some of the devices didn't last long enough for me to
lose the receipt

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raesene2
If anyone's interested in some more details for write endurance I'd recommend
Anantechs SSD reviews. [http://www.anandtech.com/show/7173/samsung-
ssd-840-evo-revie...](http://www.anandtech.com/show/7173/samsung-ssd-840-evo-
review-120gb-250gb-500gb-750gb-1tb-models-tested) .

If the numbers in those are accurate it looks like write endurance shouldn't
be a problem at least for any consumer drive. The estimate on that review was
12 years in a typical consumer setup, and I'd reckon that almost everyone
would have replaced a laptop or PC in that kind of timeframe.

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marshray
Can someone explain the discrepancy between

> I still hear stories of users thinking it's perfectly normal and economic to
> replace burned out Intel SSDs every 6 to 12 months

and

> How long have you got before the disk is trashed? ... 51 years!

~~~
Symmetry
There's a big difference between using consumer grade MLC flash and running a
very high intensity workload and using enterprise grade SLC flash and only
using 80 MB/s of bandwidth.

As a consumer you really don't have to worry about write endurance, though. I
mean, how much do you write to your drive every day, maybe 5 GB at most? Even
with MLC flash and a fairly small 120 GB drive that'll last you for a couple
of hundred years. And even when it fails you can still read the data out, you
just can't write new data. The problem you should worry about is a firmware
bug in the part of the drive that handles the wear leveling abstraction. I
haven't seen one of those in a while, but when many companies were just
starting to develop SSDs they occurred fairly frequently, though usually the
manufacturer would figure out the problem and patch the firmware for new
drives after enough failures in the field.

~~~
wslh
But, is a hybrid approach the best option? I mean an SSD for the software and
an HD for the data?

~~~
Symmetry
I actually think the best approach, longterm, would be to use the SSD as a
cache for the HD at a filesystem level. I believe something along those lines
was just merged into the Linux kernel.

~~~
supergauntlet
Yep, dm-cache essentially does what Intel Smart Response does except it's done
in the OS and not the BIOS.

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jlgaddis
Just a quick note: before you buy a "self-encrypting drive" (SED SSD), do your
research and make sure you get one where you can control the keys.

A couple of months ago, I spent almost $400 on a Crucial M500 480GB SSD to put
in a new laptop only to discover that apparently the drive itself handles the
generation of keys.

Thus, _technically_ all of the data on the drive is encrypted but you can take
the SSD out, put it into another machine, and access the data without any
issues. Total marketing ploy.

~~~
rdl
The point behind it is you can delete the key in one place and not have to
worry about erasing every part of flash in the machine (which, after
remapping, may not even be possible through normal means).

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diydsp
What are these RAM SSDs of which the article speaks? I searched around for a
bit, but couldn't find any place to order one (keep getting hits for PCs for
sale)... are they available in say, 64GB in SATA?

~~~
solarmist
He's referring to Ram disks in the article.
([http://en.wikipedia.org/wiki/RAM_disk](http://en.wikipedia.org/wiki/RAM_disk)).

The only result I found to buy was this software from AMD (to partition some
of your RAM as a RAM disk).
[http://www.newegg.com/Product/Product.aspx?Item=N82E16832385...](http://www.newegg.com/Product/Product.aspx?Item=N82E16832385001).

~~~
yareally
ImDisk[1] is free without restrictions and also open source. I just set it as
a small system startup script[2] to create a ramdrive on boot into Windows.
Makes for a nice throwaway drive for things that are read/write intensive
(like compression/extraction) or putting a mini virtual machine on and running
it purely in RAM. I also put things like my temp downloads there, page file,
temp directories, browser caches/history. I suppose you could put the scratch
drive for Photoshop on it as well, but I have never tried that.

Technically, you can also save all the files from the disk on shutdown, but
you have to wait for them to copy back, though I prefer the volatile nature of
the drive and having it wipe everything on reboot except for a predefined
directory structure that gets recreated each boot.

RAM is cheap and I ended up buying 24GB for $150 or so a while back so having
a ramdrive gives you a use for all that excess RAM. When I'm using my laptop
with 4GB I miss having the extra space a bit.

[1] [http://www.ltr-data.se/opencode.html/](http://www.ltr-
data.se/opencode.html/)

[2]
[https://gist.github.com/yareally/6199239](https://gist.github.com/yareally/6199239)
(my batch startup file example and link to a more detailed guide)

~~~
tiziano88
You put your page file in a Ramdisk? We need to go deeper...

~~~
yareally
Mainly to avoid the Windows page file from getting fragmented on a HDD, since
fragmentation on a RAM disk is a non-issue. I keep my home desktop PC on most
of the time and don't reboot often unless switching OSs.

~~~
sp332
If you have RAM free, Windows shouldn't be using your page file. If you have
so little RAM free that Windows is paging, then using even more RAM to host
the pagefile will make things worse. You might as well just turn off the
pagefile entirely.

~~~
yareally
Windows likes to use it regardless of the amount of RAM you have free. Page
File on Windows is unfortunately not as friendly as the swap area on Linux
(where what you said is true).

Currently I have 8 GB free (out of 24 GB) and the page file is sitting at 944
MB (up from 96 MB) after rebooting about 12 hours ago. Windows has always been
this way regardless of the version.

Turning it off is also not a good idea as Windows does use it regardless of
free RAM.

~~~
sp332
If moving some data to disk helps performance by freeing up RAM, then putting
the swap file back in RAM won't help because it's just taking up RAM again.
Or, if you're just worried that Windows is putting things in the swap file
that would perform better if they were kept in memory, it would be just as
effective to disable the page file to force them to be in RAM. Either way,
there's no improvement.

~~~
yareally
If you read my previous posts, the page file is far from the only reason I
have a ram drive. Since I use it for lots of other things and I rarely use all
of it, I might as well put my page file there as well. I also have 24 GB of
RAM so not overly worried about storage.

I regret mentioning the page file, because it always starts some sort of silly
debate on any forum it's discussed (Google yields tons of results).

~~~
mdpye
Windows does things like swap out applications which are minimised or not
recently used to allow more space for disk cache. You're neatly defeating the
point of swapping them out by keeping the page file in ram.

You are still shuffling pages in ram in order to "swap" them though. The gp is
correct. To achieve your goal, disable the page file. Having it on the ram
drive entirely defeats its purpose; The ram backed page file won't help you in
the case of memory exhaustion, and it doesn't allow the OS to put the ram to
better use where it judges that possible. It's your machine and your
perogative, but it is daft, and people are going to point that out.

~~~
Dylan16807
Defeating it is a good thing. I don't want to waste time waiting for programs
when I unminimize.

And windows gets cranky without any swap at all. When I 'disable' swap I
always set it to 20MB or something.

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rpedela
How does this affect cloud providers using SSDs? Are they using the reliable
and expensive version? Do they use consumer ones and then swap them
periodically?

------
jasonkolb
How does everyone else set up their dev systems? I just rebuilt my dev machine
and I'm using one SSD drive for the OS, one SDD for data (database, Cassandra
stuff), and then a regular drive to hold code and builds since that gets
rewritten several hundred times a day sometimes.

~~~
lutusp
> I just rebuilt my dev machine and I'm using one SSD drive for the OS, one
> SDD for data (database, Cassandra stuff), and then a regular drive to hold
> code and builds ...

So instead of one large storage pool, you have three. This means your chance
to have your system grind to a halt with a disk-full condition is three times
greater than it would otherwise be.

I've never understood this logic, but I certainly see it implemented a lot.
It's a new version of disk hard-partitioning in *nix systems -- a scheme that
stopped making sense once drives because large enough to contain all the
resources on one unit.

With one drive containing all stored resources and no hard partitions, there's
exactly one disk-full failure mode -- when the disk is full.

When Charles Lindbergh was asked why he wanted only one engine on his historic
Atlantic-crossing plane, he replied that, since the multi-engine planes of his
day couldn't stay airborne on one engine, his design was actually safer.

~~~
__david__
I used to have the same opinion you did until I started doing some really
filesystem intense stuff (not even big, just lots of creating and deleting of
files) and suddenly my entire system ground to a halt. Huge delays (top showed
state "D"—waiting for device).

I moved that stuff to its own disk and my system became smooth as butter
again.

I'm still not down with the traditional unix '"/usr" must be its own
partition!' thing, but it _does_ help to separate your tasks onto separate
disks.

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abalone
Zsolt Kerekes is a pretty sweet name. I don't think there is a name that says
"solid state storage" better than "Zsolt Kerekes".

~~~
pestaa
It is a simple Hungarian name and translates very roughly to Solt Wheeler.

[http://en.wikipedia.org/wiki/Zsolt](http://en.wikipedia.org/wiki/Zsolt)

