RAID 0 - Help wanted once again

[Techtu]

Okay so I've had my RAID a few week's now and can say I'm impressed, even with just 2 drives in the array, anyways I've been hearing things about the stripe size? What is this and how does it effect the drives/performance? Also is there a certain setting for any type of drive out on the market?

 

[slyfox2151]

Okay so I've had my RAID a few week's now and can say I'm impressed, even with just 2 drives in the array, anyways I've been hearing things about the stripe size? What is this and how does it effect the drives/performance? Also is there a certain setting for any type of drive out on the market?

128k or higher works the fastest in a raid0, but it also costs the most space when writing small files.


the higher the stripe size(to a point), the faster the data can be read from the drives at a cost of disk space with files small then the stripe size.

 

[Techtu]

To a point?

Well... I have 1Tb of space which I will never fill, I could never even fill my 500gb with all my crap installed and crap all over the deaktop and such, so should I really be changing the stripe size to the maximum it'll let me set it?

 

[JrRacinFan]

Ok let's put it this way in analogy. Let's call the array a page of word processing. The lower the font(higher stripe size), the more you can fit on a page(stripe cluster). If you only need to file half the page you are wasting the rest of it. So basically you are forfeiting disk space if using alot of small files on a higher stripe size.

@slyfox

not discrediting you, just trying to help techtu understand everything.

 

[Athlonite]

I've found through my own testing of Raid0 arrays that a stripe size of 64k is a good balance of speed and space usage..

larger stripe size = greater read/write speed but greater amount of wasted space (an 4KB file on an 128K stripe will waste 124KB of space)

smaller stripe size = lesser read/write speed but not as much wasted space


atto disk bench will give you a better idea where your array performs best

 

[Disparia]

You do not lose space from files that are less than the stripe.

Test for it: I just wrote out a script to write 4,000,000 files on my RAID-0 with two 250GB drives and a 128KB stripe. If the minimum space used for any file is the stripe size, then I shouldn't be able to write more than ~3.82million files, but it does work. This is because stripe size is simply a boundary the controller uses and not a 'unit' like a cluster.

 

[Techtu]

Meh... this gives me headaches, even after hours of reading other stuff about this online I'm still as clueless from when I first started

Seem's everyone has their own opinions and needs so no better way than to go change the stripe size for myself and see what works best for me I guess.

 

[JrRacinFan]

Leave it at 128.

 

[Techtu]

Leave it at 128.

It's currently set at 64kb.... I'll reboot now and change the value then I'll run Atto

 

[AsRock]

You do not lose space from files that are less than the stripe.

Test for it: I just wrote out a script to write 4,000,000 files on my RAID-0 with two 250GB drives and a 128KB stripe. If the minimum space used for any file is the stripe size, then I shouldn't be able to write more than ~3.82million files, but it does work. This is because stripe size is simply a boundary the controller uses and not a 'unit' like a cluster.

Yes thats what i thought. It more dependent on how big the average file is so if 90% of the files on the HDD are small a lower strip size would be better for that drive and of course a higher strip size if the files are bigger.

And a higher strip size would mean less fragmentation too as there is more of the file in one spot on the drive.

When i was testing it with 6 HDD's i found the games array was best around 128 ( large compressed files ) and windows around 32 - 64.

 

[JrRacinFan]

It's currently set at 64kb.... I'll reboot now and change the value then I'll run Atto

Oh well, it's ok leave it. It won't hurt anything.

 

[Techtu]

i found the games array was best around 128 ( large compressed files ) and windows around 32 - 64.

Well I have my OS & games installed on the same drive

Oh well, it's ok leave it. It won't hurt anything.

It won't let me change it anyways, say's I need to use the minimum of 2 disks... I'm sure I'm already using 2 disks, or isit a case of deleting the array and creating a new one with the new size? or would that just totally be a foolish thing to even think about doing as it might delete all the data?

 

[JrRacinFan]

Well I have my OS & games installed on the same drive



It won't let me change it anyways, say's I need to use the minimum of 2 disks... I'm sure I'm already using 2 disks, or isit a case of deleting the array and creating a new one with the new size? or would that just totally be a foolish thing to even think about doing as it might delete all the data?

Yup just remembered you would have to rebuild the array to change the stripe size.