What goes where on multi-disk systems?

[Dinosaur]

I am running a system with three physical disks. I assume that the following is the best way to organize the drives.

OS & applications software on first disk.
Data on the second disk.
OS swap file and backups for first two disks on the third drive.

It seems to me that head movement is minimized by the above organization. Since head movement takes milliseconds, minimizing it is a good idea. I think minimizing head movement also increases the mean time to disk failure.

Does anybody have an opinion on the above.

Some friends of mine have two physical disks. It seems correct to put the OS and applications software on the first disk, with the data files on the second.

Where should the OS Swap file be? Does this depend on the type of user? For example: A user who has many applications active and often switches among them is different from a user who gets on the internet and does not do much else, or from a user who keeps several applications active, but does not doing much switching (Id est: He works with one application for 30-60 minutes before using another).

Any thoughts on the above?

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Gouverneur
Eschew Obfuscation!
If one hundred million people believe a foolish idea, it is still a foolish idea.

[mjc]

Part of your question should also be how big of a swpfile...if the system has a large amount of memory (I'd say over 128MB minimum) it doesn't need to be very large, and if it has over 256MB it should be a bare minimum size (becasue you can't do away with it entirely Windows needs to have one). No, you won't see much of a performance increase with more than 128MB but you will have much less usage of the swapfile, more programs can be active at once, and right now memory is so cheap (as low as $0.13 a MB for Crucial PC2100...256MB for under $34), so I think it makes sense to max out the memory.

It should probably be on the fastest drive that doesn't contain the OS...maybe in its own partition (that would minmize fragmentation if it were on a data drive), but not really an absolute necessity...

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mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

[Dinosaur]

I am not sure that using fastest drive for swap file is correct. Head movement takes milleseconds, which is significant. Putting swap file on a slower drive that is used for nothing else could save time due to reduced head movement.

If swap file is on same drive as some file currently being used, the system might have to move heads to swap file, do I/O, and move heads back. This could be time consuming.

On most systems, all physical disks run at same speed. With three disks, Software, data files, and swap files on three different drives seems like a good idea.

Assuming a two disk sysstem with OS & application software on on disk, and data on another, I still wonder which disk should get the swap file.

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Gouverneur
Eschew Obfuscation!
If one hundred million people believe a foolish idea, it is still a foolish idea.

[mjc]

If you a large amount of memory then you aren't going to use the swapfile that often, so does it really matter?

I've got 192MB of memory installed and I can run more than I can actually keep track of before I start using the swap...

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mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

[Paleo Pete]

I always put my swap file on a separate drive, so the read/write head does not have to look in one place on the drive for data and another place for the swap file.

I think the IDE controller can check both drives at once, even if not, it turns out a bit faster to use a separate physical drive for it.

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