Subject: Summary : RAID 0 for speed?

From: Josh Bowden <[email-masked]>
Date: Thu, 06 Aug 1998 16:49:31 +0930

Summary of responses regarding RAID 0, 
thanks to you who replied.

I am wondering now is NTFS supported by Gaussian98 ?

Q1:
I am wondering if anybody has experience with RAID 0 setup for workstations running ab-initio programs. I would think that this would be a v.good way to increase disk access speed and a good way to increase disk storage space. Does RAID 0 increase integral file R/W access and therefore increase computational speed? or are other areas the bottleneck in a computer+ab-initio program? Is anyone usinig IDE HD RAID cards, such as those from Promise Tech. and have you found that these increase computational performance?

A1:
With respect to SCSI RAID 0 the answer is a big yes, yes. However if you
are using the HyperCube or Gaussian products with NT as the OS then the
answer is maybe. Both companies have limited the file size to 2GB which
they say is based on FAT 32. I have communicated with them many times about
implementing NTFS. It is a simple procedure and both companies have
indicated that they will support the NTFS file structure in their next
release. 
For FAT the max file size is 2^32 bytes (4.3 GB). 

For NTFS, the max is 2^64 bytes (1.8 x 10^10 GB). I don't think this is
much of limitation.

Laurence

Q2:
Has anyone tried the RAID 0 setup on NT (striped sets) (ie software controled RAID) and does it make any difference to disk access times/computational speed?
A2:
I have tried it and it works, but I have not compared the performance to a
non-striped set. A manual from Adaptec cites about 15% performance gain, if
the drives are on separate SCSI channels. I am not sure what the gain would
be on separate EIDE channels.
Bottom line: if you have two similar drives and want one file system -
always stripe.
Slawomir Janicki
[email-masked]

Thanks again
Josh

Josh Bowden
University of South Australia
Ian Wark Research Institute
[email-masked]