HDD or SSD as primary storage

[thricipio]

I'm getting ready to purchase a new laptop and am trying to decide
whether or not to use a conventional HDD as my primary storage drive,
or go with one of the new SSD drives.

I've already read one thread that gives me pause regarding going with
an SSD:
-----------
https://groups.google.com/d/topic/comp.sys.ibm.pc.hardware.storage/7ZgKnEUJj84/discussion

But besides this, I've heard that SSD technology has an inherent limit
to the amount of times it can write. A BestBuy GeekSquad guy told me,
"Yes, that's theoretically true, but you'd have to use the drive
24x7x52 for six years before it would become a problem, and any
mechanical (HDD) would fail long before then under such a usage
load."

I don't know... that answer sounded a little too good to be accurate,
so I thought I'd post here for some more (and probably more reliable)
input.

Any more guidance will be appreciated. Thanks. --Thri

 

[Arno]

I'm getting ready to purchase a new laptop and am trying to decide
whether or not to use a conventional HDD as my primary storage drive,
or go with one of the new SSD drives.

I've already read one thread that gives me pause regarding going with
an SSD:

But besides this, I've heard that SSD technology has an inherent limit
to the amount of times it can write. A BestBuy GeekSquad guy told me,
"Yes, that's theoretically true, but you'd have to use the drive
24x7x52 for six years before it would become a problem, and any
mechanical (HDD) would fail long before then under such a usage
load."

This is basically misdirection: "use" != "write". When constantly writing,
consumer-grade die pretty fast. Also well-treated HDDs do reach ages
higher than 6 years even running 24/7.

The issue is more subtle: SSDs are new and relatively untried devices.
While mechanical shock is not a risk, software problems and hardware
design issues are very much so. If you write a lot (e.g. lots
of downloading, viedo editing or the like), your SSD will die
young, while a HDD soes not care at all. Also, some SSDs start
to limit the write speed to very low speeds at some point in order
to reach their promised lifetimes. The german computer magazine
c't is currently conducting a long-term experiment on this with
a number of SSDs, in issue 3/2012. One got dramatically slower at
20TB, two are getting linearly slower and one dropped its write
rate to 10% after 140TB written. Four (including the ones
getting linearly slower) are fine, but just have reached
40-60TB though. This is out of 6 drives.

I don't know... that answer sounded a little too good to be accurate,
so I thought I'd post here for some more (and probably more reliable)
input.

Any more guidance will be appreciated. Thanks. --Thri

It depends on your usage patterns. If you do not write a lot
(normal usage), an SSD should be fine for 3-10 years, difficult
to say exactly at this time. It is shock-proof and very fast. It
is_not_ more reliable than a normal HDD, so a full backup is
still mandatory. Depending on the SSD, it may also not consume
less power than a HDD.

Also, SSDs have less data shelf life than HDDs. While data on
a HDD is usually fine after 10 years, SSDs may experience
data loss after a few years (3...5), especially consumer
grade SSDs. This is mostly a problem when they are not used,
as at leas some SSDs do background refreshing of data that has
started to get weak. Information is sketchy on this though.

So, do not trust them too much, but if you are willing to pay
for speed and mechanical ruggedness, go for a SSD. Otherwise
stay with a conventional HDD.

Arno

 

[Yousuf Khan]

I'm getting ready to purchase a new laptop and am trying to decide
whether or not to use a conventional HDD as my primary storage drive,
or go with one of the new SSD drives.

I've already read one thread that gives me pause regarding going with
an SSD:
-----------
https://groups.google.com/d/topic/comp.sys.ibm.pc.hardware.storage/7ZgKnEUJj84/discussion

But besides this, I've heard that SSD technology has an inherent limit
to the amount of times it can write. A BestBuy GeekSquad guy told me,
"Yes, that's theoretically true, but you'd have to use the drive
24x7x52 for six years before it would become a problem, and any
mechanical (HDD) would fail long before then under such a usage
load."

I don't know... that answer sounded a little too good to be accurate,
so I thought I'd post here for some more (and probably more reliable)
input.

Any more guidance will be appreciated. Thanks. --Thri

I would not use an SSD as your day-to-day storage drive, I'd use it only
as a boot drive for the OS, and store stuff off to an HDD, even an
external one.

I'm in the process of considering an SSD myself, to upgrade my desktop,
for faster boot times and OS installation.

But as Arno said, SSD's are new technology, they have not been proven
for their longevity yet. I would not trust their longevity estimates.
Just recall those overblown estimates of the lifetimes of CD's and
DVD's, there were estimates that they'd live 100 years, 1000 years,
whatever! Just 30 years later many are now unreadable.

Yousuf Khan

 

[Noob]

The issue is more subtle: SSDs are new and relatively untried devices.
While mechanical shock is not a risk, software problems and hardware
design issues are very much so. If you write a lot (e.g. lots
of downloading, viedo editing or the like), your SSD will die
young, while a HDD soes not care at all. Also, some SSDs start
to limit the write speed to very low speeds at some point in order
to reach their promised lifetimes. The german computer magazine
c't is currently conducting a long-term experiment on this with
a number of SSDs, in issue 3/2012. One got dramatically slower at
20TB, two are getting linearly slower and one dropped its write
rate to 10% after 140TB written. Four (including the ones
getting linearly slower) are fine, but just have reached
40-60TB though. This is out of 6 drives.

Isn't this the problem that TRIM is supposed to solve?

Tying it All Together: SSD Performance Degradation
http://www.anandtech.com/show/2829/9

http://en.wikipedia.org/wiki/TRIM

TRIM was introduced soon after SSDs started to become an affordable
alternative to traditional hard disks. Because low-level operation of
SSDs differs significantly from mechanical hard disks, the typical
way in which operating systems handle operations like deletes and
formats (not explicitly communicating the involved sectors/pages to
the underlying storage medium) resulted in unanticipated progressive
performance degradation of write operations on SSDs. TRIM enables
the SSD to handle garbage collection overhead, that would otherwise
significantly slow down future write operations to the involved
blocks, in advance.

Regards.

 

[Joseph Terner]

Arno wrote:

[...] Also, some SSDs start
to limit the write speed to very low speeds at some point in order
to reach their promised lifetimes.

[...]

Isn't this the problem that TRIM is supposed to solve?

TRIM doesn't solve the problem with limited write cycles of flash memory.
As SSD manufacturer you have two options:

1. Allow the maximum write speed and the drive dies within weeks.

2. Reduce the write speed over time, so the user needs at least 2 years
(or the warranty period), to reach the physical limits of the flash
cells. If the drive dies out of warranty, everything is fine (for
the vendor).

Joseph

 

[Arno]

Arno wrote:

[...] Also, some SSDs start
to limit the write speed to very low speeds at some point in order
to reach their promised lifetimes.

[...]

Isn't this the problem that TRIM is supposed to solve?

TRIM doesn't solve the problem with limited write cycles of flash memory.
As SSD manufacturer you have two options:

1. Allow the maximum write speed and the drive dies within weeks.

2. Reduce the write speed over time, so the user needs at least 2 years
(or the warranty period), to reach the physical limits of the flash
cells. If the drive dies out of warranty, everything is fine (for
the vendor).

That would fit the data. I had a look at that C't Article again,
dramatic drop of in onw SSD at 140TB written, two still going
at 40TB and 60TB (these are slower) and one fast drop-off at 20TB.

Will be interesting to see how this progresses.

Incidentally, there is

3. Don't lie to your customer about the characteristics of your
product, not even by omission.

But as most customers do not understand what they are buying and
have short memories, that leads to economic failure of the product.
In some areas you can at least look at the professional offerings
(e.g. Compact Flash) and compare. For example, if the 5 times as
expensive CF card only offers 5 years data-lifetime, than what can
you realistically expect from the consumer grade one?

Arno

 

[thricipio]

To one and all who replied. Thank you so much. Abundantly helpful.
For my purposes, my conclusion, based on your input: I'm going to
stick with HDD's. Seems to me SSD's are not ready for primetime in
terms of reliability and longevity. Perhaps they will be ready
someday, or perhaps an entirely new solid state technology will
arrive. In any case, thanks again.
--Thri

 

[Daniel Prince]

It depends on your usage patterns. If you do not write a lot
(normal usage), an SSD should be fine for 3-10 years, difficult
to say exactly at this time.

Do any of the current laptop computers allow the user to install a
HD and a SSD simultaneously? If some did, that would allow the user
to use a SSD where speed is really needed and use a HD for files
that are written to frequently.

 

[Daniel Prince]

Daniel,


Not exactly as you worded it, but yes you can order some that way new.
I'd then put ONLY the OS on the SSD/boot drive, and EVERYTHING else on
the HDD.

What about the EXE files of programs that you use frequently?

What size of SSD would you order if you used Windows 7 64 bit?

What size of SSD would you order if you used Windows 7 64 bit and
Linux?

 

[Noob]

How can we check to see how much have been written on our SSDs? I hope
mine are low since I started using my Corsair Force Series F115
Solid-State Disk (SSD) (CSSD-F115GB2-BRKT-A) back on Thanksgiving 2011
day for my new Debian stable installation.

Some SSDs implement SMART. That might provide some clues?

Media Wearout Indicator
Total LBAs Written

 

[Noob]

Arno wrote:

[...] Also, some SSDs start
to limit the write speed to very low speeds at some point in order
to reach their promised lifetimes.

[...]

Isn't this the problem that TRIM is supposed to solve?

TRIM doesn't solve the problem with limited write cycles of flash memory.
As SSD manufacturer you have two options:

1. Allow the maximum write speed and the drive dies within weeks.

Meh... too much hyperbole.

cf. http://www.anandtech.com/show/2829/6

Naive calculation (assuming perfect wear-leveling, no write amplification,
and 5k erase cycles) one can write ~1 PB to a 256-GB SSD.

(That's 275 GB per day over 10 years.)

More on so-called "High Endurance" cells:
http://www.anandtech.com/show/4807/intel-officially-announces-ssd-710-series-for-the-enterprise
http://www.tomshardware.com/reviews/ssd-710-enterprise-x25-e,3038-4.html

Regards.

 

[Rob]

What about the EXE files of programs that you use frequently?

What size of SSD would you order if you used Windows 7 64 bit?

What size of SSD would you order if you used Windows 7 64 bit and
Linux?

SSD only come in limited sizes - large 240Gb

Cost a bit under $1 /GB

HDD cost about 7c /Gb

your choice

The slowest part of a PC now within an average system is the HDD.

What advantages do SSD have within the system as a whole are they worth
the extra cost for a faster boot time?

 

[Krypsis]

Do any of the current laptop computers allow the user to install a
HD and a SSD simultaneously? If some did, that would allow the user
to use a SSD where speed is really needed and use a HD for files
that are written to frequently.

My 5+ year old Toshiba Qosmio has provision for two hard drives. It was
originally equipped with 2 x 160 GB Toshiba drives. I have since
replaced them with 2 500 GB units from Western Digital. The interesting
point is that the new drives are faster, use half the current and
(obviously) have 3 times the capacity. Battery life has been noticeably
extended. I don't know if the all the SSDs are of the same form factor
or if they have the same interface but it should be possible to do as
you request. The only SSD I have seen was in a netbook and that seemed
to be nothing more than a tiny circuit board.

Don't know if the new Qosmio laptops (more a desktop replacement really)
are similarly equipped. It is the only laptop I know of with provision
for two internal drives though I have no doubt there may be others.

 

[Group Admin]

I had another thought/question...

If I'm not mistaken, SSD's use the same basic technology that one
would find in smartphones and tablet computers, etc. If this is so,
it seems one would expect to see memory failures in these devices,
especially once a given model has been in use for a period of time.
Yet, I've heard no reports along these lines.

Mostly, I'm just curious about this; I'm sticking with my decision to
forego the SSD experience for the time being (at least as far as my
new laptop is concerned). And I continue to be grateful for all the
previous info. So thanks again on that.

But... I *am* interested in the implications for mobile devices, of
the info shared previously.

Regards,
--Thri

 

[thricipio]

I *am* curious about one thing, though: what are the implications of
what's been discussed for the many mobile devices (e.g., smartphones
and tablets) currently in use? That is, I believe their memory uses
the same underlying solid-state technology; yet, I haven't heard of
any memory-related problems. I wonder why not!

Thanks again for all your help.
—Thri

 

[Arno]

I had another thought/question...

If I'm not mistaken, SSD's use the same basic technology that one
would find in smartphones and tablet computers, etc. If this is so,
it seems one would expect to see memory failures in these devices,
especially once a given model has been in use for a period of time.
Yet, I've heard no reports along these lines.

Your model is flawed. These use different filesystems with
much reduced stress on the storage and avoid writing wherever
possible. You can do that for Linux (e.g.) as well and
then get years of usage on FLASH storage without defect
management or wear-leveling.

Mostly, I'm just curious about this; I'm sticking with my decision to
forego the SSD experience for the time being (at least as far as my
new laptop is concerned). And I continue to be grateful for all the
previous info. So thanks again on that.

But... I *am* interested in the implications for mobile devices, of
the info shared previously.

There are none.

Arno

Regards,
--Thri

To one and all who replied. ?Thank you so much. ?Abundantly helpful.
For my purposes, my conclusion, based on your input: I'm going to
stick with HDD's.
:
[snip]
:

 

[thricipio]

Okay, thanks. I sort of see what you're saying.

Part of my curiosity centers around interest in getting an Android-
based tablet, hopefully, in the near future. And if I understand you
correctly, then I shouldn't need to worry about adding media files to
the storage, and maybe erasing some of them, and replacing them with
other files, and maybe doing this repeatedly over the course of
however long I'd like to use the device.

It sounds like you're saying that given the nature of the device, and
the Android OS, the fact that FLASH memory has a certain rewrite
limit, wouldn't really matter in terms of practical usage over a
period of years... say 5 years? More? Less?

Anyway, thanks again. --Thri

 

[Arno]

Okay, thanks. I sort of see what you're saying.

Part of my curiosity centers around interest in getting an Android-
based tablet, hopefully, in the near future. And if I understand you
correctly, then I shouldn't need to worry about adding media files to
the storage, and maybe erasing some of them, and replacing them with
other files, and maybe doing this repeatedly over the course of
however long I'd like to use the device.

This should not be a problem, yes.

It sounds like you're saying that given the nature of the device, and
the Android OS, the fact that FLASH memory has a certain rewrite
limit, wouldn't really matter in terms of practical usage over a
period of years... say 5 years? More? Less?

Depends. It may also be that some devices do it better than others.
However I would expect that basically all will have wear-leveling
and some kind of defect management.

5 years is the usual device lifetime for nomal usage.

That said, it may well be possible to write an App that
does destroy your storage a lot faster, but it would
have to be intention or a high level of stupidity. Which
can be observed in the wild. This still is new technology
and cannot be expected to be completely reliable.

Arno

 

[Noob]

Part of my curiosity centers around interest in getting an Android-
based tablet, hopefully, in the near future. And if I understand you
correctly, then I shouldn't need to worry about adding media files to
the storage, and maybe erasing some of them, and replacing them with
other files, and maybe doing this repeatedly over the course of
however long I'd like to use the device.

It sounds like you're saying that given the nature of the device, and
the Android OS, the fact that FLASH memory has a certain rewrite
limit, wouldn't really matter in terms of practical usage over a
period of years... say 5 years? More? Less?

On a related note, you may enjoy reading about file systems designed
specifically to deal with flash memory, such as UBIFS.

http://en.wikipedia.org/wiki/List_o...timized_for_flash_memory.2C_solid_state_media

http://en.wikipedia.org/wiki/UBIFS

Regards.

 

[thricipio]

Thank you. I'll check this out.

And thanks to Arno for his last reply (Mar 16). --Thri