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Old 08-23-2012, 07:30 PM
Michael Mol
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 3:22 PM, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Thu, 23 Aug 2012 11:57:25 -0700, Mark Knecht wrote:
>
>> This limitation is likely just a byproduct of using a 1 lane
>> controller. If one was willing to spend a (fairly large) bit more one
>> could get a 16 lane SATA3 controller and would likely do much better
>> in terms of throughput...
>
> If you want real performance from SSD, you ditch SATA altogether and use
> a drive on a dedicated card. Of course, you're talking real money now.

Um. I'm pretty sure he's already getting 'real' performance from that
SSD, even a "mere" 200MB/s runs circles around my best set of platters
at home.

--
:wq
 
Old 08-23-2012, 07:34 PM
Mark Knecht
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 12:22 PM, Neil Bothwick <neil@digimed.co.uk> wrote:
> On Thu, 23 Aug 2012 11:57:25 -0700, Mark Knecht wrote:
>
>> This limitation is likely just a byproduct of using a 1 lane
>> controller. If one was willing to spend a (fairly large) bit more one
>> could get a 16 lane SATA3 controller and would likely do much better
>> in terms of throughput...
>
> If you want real performance from SSD, you ditch SATA altogether and use
> a drive on a dedicated card. Of course, you're talking real money now.
>
>
> --
> Neil Bothwick
>
> OPERATOR ERROR: Nyah, Nyah, Nyah, Nyah, Nyah!

Can you supply a link to such a solution? Just curiosity. I'm sure I
don't have the money... ;-)

- Mark
 
Old 08-23-2012, 07:43 PM
Michael Mol
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 3:34 PM, Mark Knecht <markknecht@gmail.com> wrote:
> On Thu, Aug 23, 2012 at 12:22 PM, Neil Bothwick <neil@digimed.co.uk> wrote:
>> On Thu, 23 Aug 2012 11:57:25 -0700, Mark Knecht wrote:
>>
>>> This limitation is likely just a byproduct of using a 1 lane
>>> controller. If one was willing to spend a (fairly large) bit more one
>>> could get a 16 lane SATA3 controller and would likely do much better
>>> in terms of throughput...
>>
>> If you want real performance from SSD, you ditch SATA altogether and use
>> a drive on a dedicated card. Of course, you're talking real money now.
>>
>>
>> --
>> Neil Bothwick
>>
>> OPERATOR ERROR: Nyah, Nyah, Nyah, Nyah, Nyah!
>
> Can you supply a link to such a solution? Just curiosity. I'm sure I
> don't have the money... ;-)
>
> - Mark
>

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100008120+600038468& QksAutoSuggestion=&ShowDeactivatedMark=False&Confi gurator=&IsNodeId=1&Subcategory=636&description=&h isInDesc=&Ntk=&CFG=&SpeTabStoreType=&AdvancedSearc h=1&srchInDesc=

Long URLs are long, but short URLs are unreliable. Still:

http://bit.ly/Pfa54T

--
:wq
 
Old 08-23-2012, 08:38 PM
Mark Knecht
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 12:30 PM, Michael Mol <mikemol@gmail.com> wrote:
> On Thu, Aug 23, 2012 at 3:22 PM, Neil Bothwick <neil@digimed.co.uk> wrote:
<SNIP>
>> If you want real performance from SSD, you ditch SATA altogether and use
>> a drive on a dedicated card. Of course, you're talking real money now.
>
> Um. I'm pretty sure he's already getting 'real' performance from that
> SSD, even a "mere" 200MB/s runs circles around my best set of platters
> at home.
>
> --
> :wq
>

Real performance being the combination of drive and controller. This
particular drive was spec'ed out at 500MB/S which is consistent with
what the drive did in that link I pointed at earlier this morning.

I do think now that 200MB/S is about the most I'm going to get from a
1 lane PCIe type adapter. I suspect that the biggest reason the link
you pointed me toward at NewEgg is spec'ed at 1GB/S is due to it being
a 4 lane card?

Anyway, thanks for the pointer.

Cheers,
Mark
 
Old 08-23-2012, 08:50 PM
Michael Mol
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 4:38 PM, Mark Knecht <markknecht@gmail.com> wrote:
> On Thu, Aug 23, 2012 at 12:30 PM, Michael Mol <mikemol@gmail.com> wrote:
>> On Thu, Aug 23, 2012 at 3:22 PM, Neil Bothwick <neil@digimed.co.uk> wrote:
> <SNIP>
>>> If you want real performance from SSD, you ditch SATA altogether and use
>>> a drive on a dedicated card. Of course, you're talking real money now.
>>
>> Um. I'm pretty sure he's already getting 'real' performance from that
>> SSD, even a "mere" 200MB/s runs circles around my best set of platters
>> at home.
>
> Real performance being the combination of drive and controller. This
> particular drive was spec'ed out at 500MB/S which is consistent with
> what the drive did in that link I pointed at earlier this morning.
>
> I do think now that 200MB/S is about the most I'm going to get from a
> 1 lane PCIe type adapter. I suspect that the biggest reason the link
> you pointed me toward at NewEgg is spec'ed at 1GB/S is due to it being
> a 4 lane card?
>
> Anyway, thanks for the pointer.

I linked to a category of products; Internal SSDs which directly
connect via PCIe. Currently 27 listings in that category. Lots of neat
stuff.

As for systemic performance...I'm certain your controller being only
one PCIe lane is a major limiting factor. Beyond that, there are a lot
of factors which weigh into SSD performance...which at least a few
people in here (such as Neil) can tell you about. I only know things
like SLC is often faster than MLC, that the on-drive controller's
properties can have a major impact, and that SSDs are mostly awesome
due to low latency.

--
:wq
 
Old 08-23-2012, 09:37 PM
Neil Bothwick
 
Default SSD performance tweaking

On Thu, 23 Aug 2012 15:43:05 -0400, Michael Mol wrote:

> > Can you supply a link to such a solution? Just curiosity. I'm sure I
> > don't have the money... ;-)

> http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100008120+600038468& QksAutoSuggestion=&ShowDeactivatedMark=False&Confi gurator=&IsNodeId=1&Subcategory=636&description=&h isInDesc=&Ntk=&CFG=&SpeTabStoreType=&AdvancedSearc h=1&srchInDesc=
>
> Long URLs are long, but short URLs are unreliable. Still:
>
> http://bit.ly/Pfa54T

They've come down in price since I last looked.


--
Neil Bothwick

Power corrupts. Absolute power is kind of neat.
 
Old 08-24-2012, 09:25 AM
Frank Steinmetzger
 
Default SSD performance tweaking

On Thu, Aug 23, 2012 at 12:15:20PM +0200, Alex Schuster wrote:
> Mark Knecht writes:
>
> > I'm currently just using a single large partition & ext3. I didn't
> > do anything special in fdisk so the partition might not be aligned as
> > best it could be. I don't know.
>
> […]
> The size of an erasable block of SSDs is even larger, usually 512K, it
> would be best to align to that, too. A partition offset of 512K or 1M
> would avoid this.

Unless the filesystem knows this and starts bigger files at those 512 k
boundaries (so really only one erase cycle is needed for files <=512 k),
isn't this fairly superfluous?
--
Gruß | Greetings | Qapla'
Please do not share anything from, with or about me with any Facebook service.

The advantage of RSS jokes is that you always know the newest one.
 
Old 08-25-2012, 10:22 PM
Volker Armin Hemmann
 
Default SSD performance tweaking

Am Freitag, 24. August 2012, 11:25:48 schrieb Frank Steinmetzger:
> On Thu, Aug 23, 2012 at 12:15:20PM +0200, Alex Schuster wrote:
> > Mark Knecht writes:
> > > I'm currently just using a single large partition & ext3. I didn't
> > >
> > > do anything special in fdisk so the partition might not be aligned as
> > > best it could be. I don't know.
> >
> > […]
> > The size of an erasable block of SSDs is even larger, usually 512K, it
> > would be best to align to that, too. A partition offset of 512K or 1M
> > would avoid this.
>
> Unless the filesystem knows this and starts bigger files at those 512 k
> boundaries (so really only one erase cycle is needed for files <=512 k),
> isn't this fairly superfluous?

no, if you misalign, a lot of 4k blocks might span into two erase blocks.
Which is bad. If you align correctly, you will never cross them unnecessary,
sparing your SSD some unnecessary writes and improving overall performance.


--
#163933
 
Old 08-26-2012, 02:04 AM
Frank Steinmetzger
 
Default SSD performance tweaking

On Sun, Aug 26, 2012 at 12:22:47AM +0200, Volker Armin Hemmann wrote:

> > > The size of an erasable block of SSDs is even larger, usually 512K, it
> > > would be best to align to that, too. A partition offset of 512K or 1M
> > > would avoid this.
> >
> > Unless the filesystem knows this and starts bigger files at those 512 k
> > boundaries (so really only one erase cycle is needed for files <=512 k),
> > isn't this fairly superfluous?
>
> no, if you misalign, a lot of 4k blocks might span into two erase blocks.
> Which is bad. If you align correctly, you will never cross them unnecessary,
> sparing your SSD some unnecessary writes and improving overall performance.

I don’t quite follow. If you align to 4k, then you are also aligned to 512k,
because 512 % 4 = 0.
--
Gruß | Greetings | Qapla'
Please do not share anything from, with or about me with any Facebook service.

The duration of a minute is relative.
It depends on the side of the toilet door you are standing on.
 
Old 08-26-2012, 11:41 AM
Alex Schuster
 
Default SSD performance tweaking

Frank Steinmetzger writes:

> On Thu, Aug 23, 2012 at 12:15:20PM +0200, Alex Schuster wrote:


The size of an erasable block of SSDs is even larger, usually 512K, it
would be best to align to that, too. A partition offset of 512K or 1M
would avoid this.


Unless the filesystem knows this and starts bigger files at those 512 k
boundaries (so really only one erase cycle is needed for files <=512 k),
isn't this fairly superfluous?


Yes, I think it is. When you search for SSD alignment, you read about
this alignment all the time, even on the German Wikipedia, and many
resources say that this can have a big impact on performance. But I
could not find a real explanation at all.


Besides that, it's not so easy to do the alignment, at least when using
LVM. I read that LVM adds 192K header information, so even if you align
the partition start to an erasable block size of 512K, the actual
content is not aligned. See[*] for information how to overcome this.
That is, if you believe the alignment to erasable blocks is important,
personally I do not know what to think now. It wouldn't hurt, so why not
apply it, but it seems like snake oil to me now.


Wonko

http://tytso.livejournal.com/2009/02/20/
 

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