Maximizing Raid Speed?

[Ross Birkbeck]

I'm about to buy an EnhanceBox E8 and have a query about the best way of filling it with drives, specifically relating to the question of the speed diminishing as drives get filled up vs drive size.

Is read/write speed solely related to how full the drive is as a percentage?

i.e. Would it be better to fill the enclosure with 8x1TB drives as opposed to 8x500GB, on the basis that at 50% full they both work as fast as each other, and so I would get a bigger chunk of 'high performing' raid? Or do I loose something with bigger drives?

£/GB it's about the same, and with two sets of the smaller drives I would have the extra security... but also the extra hassle...?

Thanks in advance,

Ross

p.s I plan on running them in RAID 5...

 

[Matthew Rogers]

If I remember correctly, it seems like the new 750GB and 1 TB drives are actually faster then 500GB drives. That said, the factors of how many drives you have in your RAID and how full they are go hand in hand. You might want to look at (http://www.amug.org/amug-web/html/amug/reviews/articles/enhance/e8pm/) It has a list of how much slower a RAID 5 gets as it gets fuller. Also, I believe that the E8 does not yet support 1TB drives, only upto 750 GB drives.

Matthew

 

[Bob Gruen]

Hard drives spin at a constant speed and write from the outside of the disk platter in. Because the outer circumferance of the platter is much larger than the inner circumferance more data can be stored and transferred per revolution. The bigger the drive the more data per revolution. These rates are roughly multiplied by N-1 in a RAID 5 configuration.

In a RAID 5 configuration the RAID controller must compute the parity bit and write it to disk, which takes a little extra time. When reading, the controller can ony read from N-1 disks at a time.

Overall, if you are using 8 disks with a good hardware RAID controller you should have no problems.

When doing an operation that reads and writes at the same time it is often beneficial to use 2 disks. So you might render a scene by reading from your external RAID system and writing to an internal disk. also, understanding how your computer manages virtual memory can allow you to configure your system to effeciently use it's disk resources.

Bob

 

[BASSAM MSSALATIE]

Thanks Bob.. i can understand that it is much better to use raid 5 enclouser

As storge for later use as reading source .and writting should be into internal

Drives ??

Will it be much better ??

 

[Anders Yarbrough]

check out caldigit.com, superfast data flows. Really neat stuff over a speedy version of ESATA.

 

[Ross Birkbeck]

thanks guys!