Best Stripe size for SSD

[Mkelliny]

What is the best Stripe size for two 256 GB samsung SSD's in RAID 0? I have read 64/128 and i have also read go as high as possible. I have never set up raid before.

and what other Values should I change if any

what about stripe width?

I am going to have everything loaded on this games, files, and Windows 7 home premium

What should I pick when i do it tomorrow?


this is going to be done on an Alienware M17x-R2 and the SSD is: Samsung SSD PB22-JS3 FDE 2.5" 256gb

these are the same as the OCZ summit SSD's i read

 

[sub mesa]

128KiB since simple RAID implementations don't allow you to go higher. You did not specify the RAID engine that you will use. RAID is a theory; you have a product that implements it. It is like the difference between a "car" and a "BMW Z3"; the last mentioned is a car but not the most perfect car ever made. Same goes for your RAID engine.

After installing check with AS SSD if the partition is properly aligned; should say something like "1024K - OK".

 

[Mkelliny]

It said it was Intel Raid how do i go further to check exactly what it is and yah the highest i can go is 128KiB performance is ok my read speeds are higher but my writes took a plunge...Ima try a 64KiB stripe size now


I did this through my BIOS after I enabled RAID 0 it said Intel

 

[billmeier]

I have an INTEL SSD and the Intel Rapid Storage Technology Manager you use to configure RAID sets with a Windows GUI, says the default stripe size for RAID 0 is 128KB for SATA disks, and 16KB for SSD's ...

My guess is that since reducing writes with an SSD is important to increase it's life, having a smaller stripe size doesn't end up writing as much data.

The latter is my theory, the former is in the Intel documentation...

Bill

 

[RetiredChief]

Myself I perfer a strip size of 8 -> 32k (Limited to 64K on this system) for the operating system + programs and a large stip size for my pair of drives holding pitures and Large video files.

If you look at mean file size for the files a drive that holds the operating system Plus program files you will find that it is around 16K to 32 K (note Average file size is skewed high due to the smaller # of Large files). Files are broken in to a "block" size 1/2 the strip size and blocks alternatly wrritten to each hard drive. Files smaller than the block size are written to only one HDD.

Where large video files are concerned the files are large - .vob's are aroung 1 Gig, HD video file can approach 30 Gigs. Picture Bitmaps/jpegs can often averge greater than 1 meg, hence a much larger strip size is better.

There is much more to this than just file size such as IO (sub mesa is better versed on that subject).

While benchmark programs can give you an Idea they do not always relate to real life. Two systems that are identical with very simular programs installed can show a difference in real life while they may benchmark identical due to file location (order of install) and how the user uses the system.
Take a look at:
http://www.techspot.com/vb/topic1596.html

could not find any objective performance comparing different stripe sizes

 

[adampower]

It seems to me the 'erase block size' on Intel SSDs seems to be 128k. So what benefit is there in a lower stripe?

 

[adampower]

Okay, we're talking Samsung... and I don't know... I do wish I could edit or delete my posts just now.

 

[billmeier]

Myself I perfer a strip size of 8 -> 32k (Limited to 64K on this system) for the operating system + programs and a large stip size for my pair of drives holding pitures and Large video files.

While that might be a good heuristic for picking strip sizes in general, I think the more general question being asked hear is should you pick a different strip size for an SSD vs HDD?

Yes, perhaps the value for an SSD relates to the erase size...

Yes, this may be Intel specific, but for the Intel SSD, the erase size is 128KB, but the documentation recommends 16KB for RAID0, which of course is much smaller than the erase size.

Perhaps the better question is why would you set the stripe size of an SSD less than the erase size? Clearly Intel believes you should, but doesn't say why...

 

[Mkelliny]

Best answer selected by Mkelliny.