Stripe sizes for two drives

[caff]

Today I'm setting up two RAID arrays in my new machine. This is the first time I've tried RAID on a home PC so I've no idea what performance to expect.

First raid array will have two drives in RAID-0, will be my C: drive used for windows, applications, games - anything that can be installed.

Second raid array, again two drives in RAID-0, will be for my data, music samples, videos, MP3's etc. - most of which will be large files (min 5mb)

Question is, what stripe size should I use for each drive? I've read various comments saying 32kb is a good average for a Windows array, and 128kb is better for media drives. Is this about right? I'm not interested in benchmarks - just real world performance.

 

[Mr-White]

so you're creating 2 RAID array with 4 drives ?

why not create 1 array spanding the 4 drives and just create 2 partitions ?

MW

 

[caff]

Would that be the fastest setup? If so, what RAID should I use?

My motherboard (Asus P5W DH) apparently supports RAID 0+1 using 4 drives, which sounds like it could be good - is this as fast as RAID 0 alone?

 

[Mr-White]

RAID 0 with 4 drives splits the data over the 4 drives so in theory you'll only be saving and transfering 1/4 of the data as opposed to 1/2 with 2 drives. RAID 0+1 is a strip and a mirror so 2 drives are striped for performance and the other 2 drives mirror the first 2 for back up purposes. The mirrored drives don't show up in windows as they work in the background. but if you loose any of the drives you'll be able to rebuild the RAID with the backup.

MW

 

[dheyworth1981]

I believe RAID 0+1 is a mix of striping and mirroring....so using 4 drives you will only get the capacity of 2, but at the full speed...and a redundancy if one of the drives fail.

Using 4xDrives in a single RAID 0 will be fastest, but if any of those drives fail then you will lose all your data

Using 2xDrives in 2xRaid 0 will give you a nice increase, but still if any of those drives fail, then half the data will go.

 

[caff]

Thanks

I think I will try the 0+1 - having some redundancy might be a good idea. It looks fairly straightforward to setup too. I'll try sticking with the default 64kb stripe to see how it goes.

 

[ernysmuntz]

I've dont a **** load of testing and stuff on this about a good couple of years ago....

I found that 16k stripe\16k cluster works best. thats for 2 or 4 drives in raid0

Tested best performance on an Sil3114 and nvraid controller.

its a pain in the ass testin stuff like this out, ATTO and other benchmarking tools don't give the true picture.

Best thing to do is to see how fast DVD Shrink can copy an iso (uncompressed from one array to another) but you need 4 drives (2 x raid0 with same config)...

So that way you get a real transfer rate test and no simulated crap.

Don't swear. FF.

 

[ernysmuntz]

Thanks

I think I will try the 0+1 - having some redundancy might be a good idea. It looks fairly straightforward to setup too. I'll try sticking with the default 64kb stripe to see how it goes.

Seriously wouldn't bother, unless you have absolutely critical data on your drives.

I been running a raid0 4 drive thingy for about 18 months with zero problems (well i've had problems, but nothing Raid0+1 would have helped, and nothing to do with a drive actually failing).

Serious waste of time unless its like for business\money is depending on it being operational 100% of the time

 

[ernysmuntz]

so you're creating 2 RAID array with 4 drives ?

why not create 1 array spanding the 4 drives and just create 2 partitions ?

MW

That would be slower

Creating 2 partitions and treating them as seperate drives is a BIG mistake.

I sometimes have a 2x2 setup if im doing video encoding, so its got a smooth path from input to output

from one raid0 array to the other (fastest)

If you creat 2 partitions, its just going from one part of the drive to another, reading\writing to the same set of drives at the same time is VERY inefficient, and you might as well not have raid0 at all for the performance it (won't) will bring.

Drives have certain "seek" times, that doesn't get decreased by Raid0, so when the drive is "seeking" between the 2 partitions, it will bring the raid0 performance right down...

 

[snowdog]

Seriously wouldn't bother, unless you have absolutely critical data on your drives.

I been running a raid0 4 drive thingy for about 18 months with zero problems (well i've had problems, but nothing Raid0+1 would have helped, and nothing to do with a drive actually failing).

Serious waste of time unless its like for business\money is depending on it being operational 100% of the time

I totally agree, paying double for the data isnt worth it, just do 4 drives in raid 0 its a bit faster and it has double the size of 0+1...

 

[caff]

Hmm, well in the end I bottled it and went for two drives in RAID 0. Windows explorer seems much more snappy.

I'll think about what to do with the other two drives - most likely either in another RAID 0 array, or just seperate standalones.

As a by note, these Samsung are silent! Very nice