Monday, April 30, 2007

Disk Disk Disk

I think the one of the upcoming challenges for the 4 and 8 core workstation market is going to be resolving a major problem for multi core systems. I/O contention.

In the 4x4 we have two processors with a total of four cores, soon to be 8. So much CPU - and yet I find that I still wait. So I must of course ask the question "What am I waiting for?". Invariably the answer is the hard drive. As I continuted to cogitate I realized now that the machine can run four concurrent processes - system or otherwise, and there can be 4 active threads ( minimum ) that would be able to and need access to the hard disk. Each thread on it's own is quite capable of saturating the hard disk with requests.

With 8 threads running concurrently we're going to have even more trouble feeding them the data that they need. It's an unfortunate scenario because there does not seem to be a decent answer.

For now I see the most viable option is to add between 4 and 8 disks to your system. I will elaborate.

To truly take advantage of the 8 cores I think that we'll need the following:

Drives Purpose
1/2 (R0) System Disk
1/2 (R0) Program Files
1/2 (R0) User Data
1/2 (R0) User application data (My Documents, Music, Etc.)

These are all areas that are accessed very frequently and demand a high level of I/O. The nvidia chipset has a large number of SATA slots, and it's possible that the designers were thinking that it would be wise to use them all. I can see now, why this is the case.

This is likely overkill - you could probably get away with using 2 of the 4 sets. But if you need and use Virtual Machines a 3rd or 4th set is not out of the question.

I suspect there would be performance boost, but I'm not entirely sure how we'd go about measuring this.

Just food for thought.

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