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Vax · Dec 11, 2001, 09:23 PM

Greetings,

i am going to setup my ibook with MacOS X 10.1. But is it better to set up Mac OS X with a seperated swap partition or not? And when yes, how to setup it?
Any experienced Mac OS X users out there?

Vax

Agent69 · Dec 11, 2001, 09:29 PM

Originally posted by Vax:
<STRONG>Greetings,

i am going to setup my ibook with MacOS X 10.1. But is it better to set up Mac OS X with a seperated swap partition or not? And when yes, how to setup it?
Any experienced Mac OS X users out there?

Vax</STRONG>

www.macosxhints.com has a page on this. Also, Resexcellence did as well, some time back.

Agent69

yuriwho · Dec 11, 2001, 09:38 PM

I did it on two machines. It makes a difference only if you don't have much ram on a machine without a fast hard drive (old powerbooks for example). The tradeoff is that you loose some disk space and have yet another thing to administer with every upgrade to the OS. If you have <256 MB ram and can't afford more on a portable then I would consider it. Otherwise it's not really worth it.

Y

Originally posted by Vax:
<STRONG>Greetings,

i am going to setup my ibook with MacOS X 10.1. But is it better to set up Mac OS X with a seperated swap partition or not? And when yes, how to setup it?
Any experienced Mac OS X users out there?

Vax</STRONG>

Toyin · Dec 11, 2001, 10:16 PM

I tried it on my DualG4 with tons of ram and 2 hardrives. It didn't make any significant difference since I rarely have pageouts (use Virtual memory)

From the research that I did, it seems that you won't really notice a speed difference if you use a different partition because the head of the hardrive still needs to bounce back and forth when it starts using VM. The benefits are only seen when you use a seperate hardrive then your system hardrive. So with an ibook I wouldn't waste the hardrive space for this alone.

selkirk · Dec 12, 2001, 12:16 PM

Don't bother on an iBook. Do buy as much RAM as you can afford.

foamy · Dec 12, 2001, 02:27 PM

I agree, don't bother on an iBook.

I noticed a significant improvement on my B&W with the swap on a separate drive. I the partition is on the same drive, then the advantage is minimal.

Imagine you are getting low on physical memory and you launch Word. The head of the harddrive has to find the Word data AND page out RAM so that you can put Word into RAM. It can't do both at once on the same drive. With the swap on separate drives, word can be read at the same time vm is paged out to the second drive. At least that's how I understand it.

ervier · Dec 12, 2001, 02:33 PM

I just bought a new harddrive for my G4, and was just wondering about this. One problem I noticed is that the standard partition program has a minimum swap-size of 2.9 GB, a bit too much I guess. Are there any other apps that can do this?

cutterjohn · Dec 14, 2001, 04:17 PM

one note, while general performance may not improve if the partition is on the same drive as the main system, I suspect that it would, potentially, reduce fragmentation of the main drive if physical memory were limited. Why? if someone with limited physical ram run ALOT of apps the virtual memory space is expanded & contracted to & from original/default size(I believe, I haven't sorted closely enough through the Darwin code yet to verify this, but it seems to be the case on an ibook dual USB 384M/10G)

If, and only if, this supposition regarding expansion & contraction of swap space from the original size is true, then aggregate performance SHOULD be helped by having virtual memory live on its own partition.

This is especially true if the system in question is an HFS+ install as HFS+ does NOTHING about fragmentation. A UFS based system SHOULD suffer less from fragmentation, but again this is dependant upon file system support as implemented by Darwin. Personally, I wish that Darwin had implemented a swap space optimized file system similar to the way Linux does.