SSD --- The reliability of

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

Threaded View

Please pardon me if this topic has been discussed before, but as far
as I know about the Flash memory, they have a relatively low limit on
re-write, as compared to hard disk

In situation where database use in concern, read and write operation
takes place very often

I know that there are pros and cons in this issue, but basically my
question is this --- How reliable is SSD?

Re: SSD --- The reliability of

Penang wrote:
Quoted text here. Click to load it

How long is a piece of string?

I don't care to belong to a club that accepts people like me as
members. Groucho Marx

Re: SSD --- The reliability of

Quoted text here. Click to load it

This is a maturing market and it seems that answers must vary
depending on what technologies are used in a specific device. For a
couple of pointers see

Note Samsung's comment in particular in the second link. Of course
manufacturers will try to allay fears.

Why not try one or try a couple of them in raid-1 form - and, of
course, take regular backups? I've seem a number of hard disks fail so
don't expect perfection from either technology.


Re: SSD --- The reliability of

Question how many times do you read write to a hard drive in a year?
Question how many times do you think you will read write to a ssd in a year?

Then go and buy a usb stick and read write to it then come back and tell us
how long it took you break it. And how many read write operations it took
to break it.

I assume we will hear from you in a couple of years.

Re: SSD --- The reliability of

Quoted text here. Click to load it
Quoted text here. Click to load it
tell us
What about swapfiles, mate?


   _____  ____  ____ __ /\_/\ __      _ ______   _____
  / __/ |/ / / / / // // . . \ \ |\ | / __ \ \  \  __\
 _\ \/    / /_/ / _  / \     / \ \| \| \ \_\ \ \__\  _\
/___/_/|_/\____/_//_/   \_@_/   \__|\__|\____/\____\_\

Re: SSD --- The reliability of

Quoted text here. Click to load it

Erm, millions?
Upon millions?
Open task manager, click View->Select Columns, and add Page Faults, I/O =
Reads, I/O Writes.

If it's your first time, you may be shocked and appalled.

Re: SSD --- The reliability of

On Tue, 11 Aug 2009 23:30:35 -0700 (PDT), Penang

Quoted text here. Click to load it

If you want to find a useful answer, you will need to dig much
deeper into this matter.

What harddisk? A US$ 50 2.5" laptop harddisk ? or a US$ 1000
15.000 rpm SAS server drive ?

What SSD ? NAND Flash, NOR Flash, single cell, multi level cell ?

As a rule of thumb: Flash doesn't just replace magnetics.
To justify the use of flash memory, you will need at least one
other reason.
And --very important, imho-- a file and operating system that is
tuned to flash, while all current mainstream OSs are disk-tuned
only :-)

Kind regards,
Gerard Bok

Re: SSD --- The reliability of

On Tue, 11 Aug 2009 23:30:35 -0700 (PDT), Penang

Quoted text here. Click to load it

We cannot reasonably generalize this, it depends on your
specific database use, how often and the amount it would
write/rewrite data versus the total capacity of the SSD.

Consider that if the database is 4GB and you have an 8GB
HDD, so it has 4GB free space, the wear-leveling feature of
an SSD would write 7X more often to each free area than if
you had 4GB database and a 32GB SSD (28GB free space).

That 7X could be very significant, suppose the SSD would
last 2 years if 8GB total or 14 years as 32GB total.

I haven't yet mentioned MLC vs SLC flash chips, chosing the
latter typically extends write cycles by roughly 10X.  Now
in the above context consider a lifespan of 2 years or 10 x
14 = 140 years.

When all is said and done, if you pick the right SSD for the
job including it having excess capacity, it is far more
reliable than a mechanical hard drive is.  MUCH MUCH more
reliable, nobody in their right mind would use a mechanical
HDD for more than a single-digit # of years for any
important database use, that single-digit number of years
closer to 0 than to 9.

Re: SSD --- The reliability of

Quoted text here. Click to load it

   Nobody knows.  It hasn't been in wide use long enough.  Bear in mind, =
though, that it is much higher quality memory than used in USB flash =
drives, so it should last quite a bit longer than your basic 16 gig =
stick for $24.99.  

Re: SSD --- The reliability of

Penang wrote:
Quoted text here. Click to load it

The last page of the report addresses "wearout" as a function of writes.
As far as I can tell, they use the best kinds of writes (large sequential),
to make the estimate.

The flash block size is 128KB. If you want to update 4KB of that,
you have to rewrite the whole thing. So relatively speaking, it is
"32x" more expensive, to deal with the small sized write.

To understand whether SSD may be of value to you, you need to know
how much data you write per day. If it is a small amount, then it may
not matter what size the writes are. If you write large amounts of
data, then you'd want to understand the characteristics very well.
(That means sorting all the writes into "size bins".)

Before you buy anything, you should also read some recent reviews
of SSD products, and some of the performance problems they can have.
Don't just buy the SSD with the lowest price. You're regret it.
This is a hint as to what you're looking for. There are more articles
around, which test for this.

If you want to build a test system for evaluation, use Intel
X25-E SSDs.


None of the above addresses "reliability" as such. The above addresses
"wearout", where you know the thing will eventually fail, as a function
of how many writes you've done. Wear leveling makes the most of the
write cycle limits of SLC or MLC flash chips.

Reliability takes into account other things, like how often a
flash chip just rolls over and dies for no particularly good reason.
Take the stick of RAM in my previous computer as an example - one entire
chip stopped responding, after about two years of usage. Why did that happen ?
That is an example of something not accounted for as wearout -
that is a device failure unrelated to usage. RAM should not
wear out. And yet I've had failures at the two year mark (the
stick was not abused, and the computer case is cooled well).
If the chips in a flash drive do that too, then not only would
I have wearout to consider, I'd have device reliability
(chips dying) to add to the effect. And the only way to study that
in any effective way, is to get field return data for SSD drives.
And nobody gives out field return data.


Re: SSD --- The reliability of

Quoted text here. Click to load it

One funny thing is --- Intel has just announced the suspension of
their X25-E SSD product

Reason? Technical

But rumors of pre-mature deaths of the SSD may cause Intel to think
twice about selling products that don't work

Quoted text here. Click to load it

Re: SSD --- The reliability of

Penang wrote:
Quoted text here. Click to load it

Are you talking about the problem that was fixed after a firmware update was
as spoken about on the following link?,8432.html

Re: SSD --- The reliability of

Penang wrote:
Quoted text here. Click to load it

Link ?


Re: SSD --- The reliability of

Paul schrieb:
Quoted text here. Click to load it
Hi Paul

here is one of the many links:

Further infos and bg infos is here /

search for
'Why Consumers Can Expect More Flaky Flash SSDs'

Richard Kofler
Dienstleistungen GmbH

Re: SSD --- The reliability of

Richard Kofler wrote:
Quoted text here. Click to load it

As I don't have a Digitimes subscription, I had to use a paraphrased article
here, translated from Russian to English. This is just the BIOS password
issue, and not an issue with the flash chips.

"  intel has suspended the supply of ssd-drive a new generation

    Published: 31.07.2009, 12:02

    Corporation INTEL [1] confirmed the existence of a problem with
    own solid-state drives next-generation ...

    ... And reported the suspension of deliveries.

    Hovye SSD drives are manufactured with the use of
    34-nanometer technology. Compared to the available market
    intel ssd-storage devices are more
    high capacity, enhanced performance and lesser

    The issue in question relates to an error in the embedded
    Software SSD-drives. In the case of user installs, and then
    try to edit or delete password BIOS, may fail, resulting in
    owner of the PC will lose access to information stored on
    solid-state disk.

    Users who have already bought a new generation of SSD, Intel
    strongly recommends not to proceed with the manipulation of password
    BIOS. The company works hard to eliminate mistakes and promises
    issue a corrected version lproshivki within two weeks.

    Added that the 34-nanometer Intel solid-state drives now
    made in the form 2.5 and 1.8 inches and are offered in
    modifications of the capacity of 80 and 160 GB.

    Prepared based on DIGITIMES [2].

    [1]: /
    [2]: "

A firmware patch for the BIOS bug was released Aug 10.


Re: SSD --- The reliability of

Penang schrieb:
Quoted text here. Click to load it

Hi Penang,

sorry for joining in so late, but I did not have access to
usenet the last 4 days.

You will find a  l o t  of useful information at

To make it short:
A flash disk is not a real SSD.
Real SSDs do like 16K IOPS per disk
and they are very reliable, very expensive and
on the market for like 20+ years.

There are 2 types of flash disks: SLC (single layer) -
smaller (i.e.upto 64GB), more expensive and faster.
MLC (multi layer) - those are bigger (upto 512GB from
Toshiba) usually 256 GB now and in the EUR 600 price
range for 256 GB.

So if a flash disk 'wears out' first thing to happen is,
that is gets slower, much slower, that is, and in a
short period of time (exactly this is Intel's problem atm).

After a long period they finally are so slow, that I think
they might never die from wearing out .....
I am not that far in testing, though.

What I do in week 9 atm is trying to do harm to the
ones I testing. I give them 2800 IOPS writing only
and 2 KB blocks only. I have to types: internally
having 4 KB blocks or 8 KB blocks.
So I write 86400 x 2800 blocks per day for 64 days now.
None is slower that at the beginning - so far.

If you can throw in a lot of money, have a look
at the real speed: Texas Memory Systems

Or on a much cheaper scale: the 12 slot boxes from (in heavy use at CERN, Switzerland).

And  n e v e r e v e r  go RAID5 using a flash disk!
Writing the parity there kills a third of the lifetime. has all on RAID5 and why never it is a good


Richard Kofler
Dienstleistungen GmbH

Re: SSD --- The reliability of

On Fri, 14 Aug 2009 22:50:17 +0200, Richard Kofler

Quoted text here. Click to load it

In some cases a third of the lifetime would be a trivial
amount to lose.  The big mistake many seem to make when
considering flash limited write-cycles is they are trying,
deliberately trying, to fill the whole drive.

Instead of leaving a few GB of free space, if a drive is
selected that has 4X as much free space, you quarter the
write cycles.

That could be a substantial difference, supposing it might
last 16 years instead of 4.  I don't mean to suggest flash
is a universal replacement for other solid state storage but
for most uses it is more reliable.

Site Timeline