Do raid arrays benefit from more Hard drive memory

[vorgusa]

I just recently put a Raid array together with an ARECA 1220 with 4 320Gb 7200.10 and was curious about the difference the hard drives make if they are in a RAID aray.. I would definetly assume there would be a benefit to getting data quicker from the Hard drive disk, but does the RAID array benefit from having more memory in the hard drive?
I was also curious about the future hard drives that will have flash memory to store a lot of information on them, do you guys think RAID arrays will be able to benefit from them or even use these hard drives?

 

[corkyg]

Hard time figuring out what it is you are asking. Are you referring to a drive's on board cache memory? Are you asking if in a RAID 0 array, do the two caches add up? In A RAID 1 array, do they add up? The letter is easier. Since the two drives are seen by the system as one drive (w/mirroring) the cache doesn't change to the best of my knowledge. As for RAID 0, I don't know. It's a good question. And what is the real world effect on data throughput?

On long, lengthy file transfers, I can't see it making much difference. ???

 

[vorgusa]

hmm kind of hard to explain.. I guess an example would be in any RAID situation would you get increased performance with a 16MB cache instead of an 8 mB cache when you have a raid controller with 256MB for caching...
and would windows be able to see features like the future flash memory Hard drives that are coming out or would it just be looked at like a regular hard drive.

 

[corkyg]

In general, increased cache sizes to improve performance when you are doing lots of different things with fairly small files. That is where the cache works. On a long, sustained transfer, the cache is somewhat out of it. As for future HDDs with larger flash memory, it would seem reasonable that there would be some advantage - if not, why buy?

I think it is also important to specify what RAID mode.

 

[vorgusa]

the future HD will start including flash memory.. the current ones do not have it. and I heard that they will mainly just work for Windows Vista and not Windows XP, but if the HD is behind a RAID array then how would the OS be able to tell it is there is my question.. I am mainly currious if the OS will be able to take advantage of features like this.

 

[corkyg]

I believe the OS reads the array as a drive according to what the RAID controller tells it. I suppose we'll find out in due course before we have to.

 

[d3n]

I would have to say if you are using an SCSI controller and about 5 disks then your getting about all your going to get as far as speed. With SATA I think the number of spindles on an array nets you more IO throughput that the increase in disk buffer

 

[vorgusa]

haha lets hope.. hopefully a firmware update will allow the system to benefit from those hard drives using the raid array