Welcome to the MacNN Forums.

dmetzcher · Nov 4, 2006, 12:52 PM

I'm getting a Mac Pro in a few weeks, and want to set things up right when I get it. I have not partitioned the drive on my iBook before, so I'm a little clueless as to whether or not I should be doing so with the Mac Pro. I'd like to keep file fragmentation at a minimum, so that's the reason for this question.

First, I'll have a 500GB drive to work with. OS X will be installed on this drive.

I use Photoshop regularly, and would like to become more familiar with video editing software and, possibly, audio editing software.

Having said that, should I partition, and why?

I would also like to know about putting swap files on the second partition (do I need only a second, or do I need multiple?). What do I need to know about this? Is it worth it? Does it keep file fragmentation low, and will that really result in a faster machine?

Basically, a second partition for a scratch disk for software that needs it, and for the swap files, is what I'm thinking might be good here. If so, how large should this second partition be? 10GB? 20GB? larger? I'm not looking to put applications on it, or store important files there. I just want to use it, if possible, to make things on the Mac cleaner and faster.

Thanks!
(This, I think, is the last loose end to tie up before purchasing the Mac Pro and the extra hard drives.)

TETENAL · Nov 4, 2006, 01:06 PM

Originally Posted by dmetzcher

I'd like to keep file fragmentation at a minimum

Then obviously you should not partition your hard drive. Partitions are just that, (free space) fragments. Only that they are fixed sized, always there fragments of your hard drive. And the operating system already does a) defragment small and medium sized files automatically and b) keeps disk fragmentation at a minimum with newly created files. And the latter works better the more free space you have on a volume. A fragmented disk has less free space on each resulting volume which means more fragmentation in files.

The only good reason to partition a disk is when you need to because you are installing multiple operating systems on it. Otherwise don't do it.

amazing · Nov 4, 2006, 01:14 PM

You're getting a Mac Pro, which has multiple HD bays. Leave the main HD unpartitioned and watch the ads for SATA HDs on sale or on rebate--which you will use for your scratch disk.

You can check places like outpost.com and dealmac.com for HD bargains.

chrismear · Nov 4, 2006, 02:07 PM

I really wouldn't worry about fragmentation too much. HFS+ does a very good job of avoiding fragmentation in the first place. And as TETENAL says, the system appreciates it if you have lots of free space available for it to do its thing.

As for the application swap file issue, you only really get a benefit if your swap files are on a completely physically separate drive. Then your system drive can be doing its thing, while simultaneously your swap drive is reading from and writing to the application swap files.

If you have the swap files on the same physical drive as your system, then the drive has to jump backwards and forwards between your swap files and other stuff. It can't simultaneously return data from both areas. This is true even if you have separated that drive into two (logical) partitions -- it's still one physical drive, so you won't see any performance benefit.

dmetzcher · Nov 4, 2006, 06:02 PM

Thanks for the replies. That was the information I needed. The initial configuration will be as follows.

Drive 1: 500GB - Mac OS X
Drive 2: 160GB - Windows XP (gaming, work apps, etc.)
Drive 3: 500GB - Backups for Drives 1 and 2, and scratch disk for OS X (initially, see below)

I suppose, given what you are all saying, that, for a few months, before I get a 4th drive, I can always use the 500GB backup drive as a scratch disk as well. I could partition it as follows.

Partition 1: 350GB - HFS+, Mac OS X clone (of Drive 1 above)
Partition 2: 100GB - FAT32, Windows XP clone via Norton Ghost (of Drive 2 above)
Partition 3: 50GB, or whatever is left over - HFS+, Scratch Disk and swap file storage

How would that work? Would 50GB (or whatever is left over) be enough room for swap files and video editing? (I guess I could increase it later, if necessary, and just reclone OS X and Windows, if I had to.

This would be temporary, until I could get a 750GB drive for the backups, and swap, to replace the 500GB drive being used for that in the beginning. Then, the extra 500GB drive would be used for file storage (I have TONS of files that are on external drives, and will want to move them to a single drive, NOT on my OS X startup volume, in the future).

Also, is there documentation for making another drive/partition the one used for the swap files? Is this even worth it? I plan on going from 1GB RAM to 3GB within the first two months.

(As you can see, I'm only concerned with relocating the swap files for OS X. WinXP can suffer, for all I care. I'll be wiping that drive every six months anyway -- which is pretty typical for me -- so it won't matter.)

Thanks again for answering my questions. I feel like I'm almost there. I can almost smell the new Mac Pro now.

dmetzcher · Nov 4, 2006, 06:07 PM

Originally Posted by chrismear

As for the application swap file issue, you only really get a benefit if your swap files are on a completely physically separate drive. Then your system drive can be doing its thing, while simultaneously your swap drive is reading from and writing to the application swap files.

This makes total sense, and I've read this before. I guess I forgot until I saw it here again. Lots of other questions about hard drive models had been asked in other threads, so this whole swap file thing was a secondary issue that I just started thinking about now. Thanks for reminding me. It changes everything a little now.

sc_markt · Nov 4, 2006, 11:19 PM

I've had my HD partitioned and like it this way. Once, I was screwing around with OS X and I could not get the computer to start. All I had to do was hold down the option key and the drive icons came up, I booted up in the other partition, went online for help and fixed the problem.

Just my 2 cents...

- Mark

dmetzcher · Nov 5, 2006, 01:18 AM

Originally Posted by sc_markt

I've had my HD partitioned and like it this way. Once, I was screwing around with OS X and I could not get the computer to start. All I had to do was hold down the option key and the drive icons came up, I booted up in the other partition, went online for help and fixed the problem.

Just my 2 cents...

- Mark

That sounds similar to what I'm going to do. The backup clone of my startup volume will be on the second 500GB drive, along with the scratch partition and the Windows clone partition.

chrismear · Nov 5, 2006, 04:33 AM

Originally Posted by dmetzcher

Partition 3: 50GB, or whatever is left over - HFS+, Scratch Disk and swap file storage

How would that work?

My gut feeling is that you'd get better performance having your system swap files and your application scratch files on separate physical disks, if you can.

Also, is there documentation for making another drive/partition the one used for the swap files? Is this even worth it?

macosxhints has a page about this, which is as good a place to start as any.

In my last post, I didn't realise you were talking about the OS X virtual memory swap files. I thought you were just talking about application specific 'swap files', like the scratch files that Photoshop and Final Cut Pro create.

Moving the actual system swap files doesn't look like something that's 'officially supported'. Personally, for a simpler life, I'd be inclined to just leave them on the system disk and tell my applications to use another physical disk for their scratch files. Chances are that'll give you a decent performance boost from that alone.

Undoubtedly there is potential for some performance benefit if you have one drive for your system and apps, another drive for your VM swap files, and another drive for your application scratch files. I'm just not convinced that the real world benefit is worth all the hacking around. Is there anyone who's tried this who'd care to weigh in?

Originally Posted by sc_markt

I've had my HD partitioned and like it this way. Once, I was screwing around with OS X and I could not get the computer to start. All I had to do was hold down the option key and the drive icons came up, I booted up in the other partition, went online for help and fixed the problem.

Absolutely, a spare partition for an emergency boot disk is a great idea (if you can afford the space!). Having a second OS installed is a excellent example of something that requires a second logical disk, but where having it on a separate physical disk isn't absolutely necessary. So partitions make perfect sense for that.

Of course, if you can get it on a separate physical drive then that's even better, because you'll have a back-up in the case where your main hard drive actually dies. But on a laptop or something, having a little emergency boot-up partition isn't a bad idea at all.

jasong · Nov 5, 2006, 10:59 AM

Chriismear, if I'm reading you right, you are saying to keep a clone on a partition instead of a separate disk. This will help if you trash your installation, but will be of no use if your drive crashes. Honestly, I have seen way more instances of HD failures than OS X installation failures, so I would consider this carefully.

chrismear · Nov 5, 2006, 11:18 AM

Yeah, I totally agree with you. I'm just saying that what sc_markt suggests is a good idea if you haven't got a second drive. But, as you say, ideally you want a second physical drive for backups.

bowwowman · Nov 5, 2006, 01:55 PM

Yes, to make a back-up/clone useful, it must be on a seperate drive. Having it on a partition of the same drive is essentially pointless, since 99.9% of major crashes are due to DRIVE failures, not the OS......

BTW, with reference to the swap file questions, I used the terminal commands at: Moving the swapfile in Mac OS X 10.4 (Tiger)

and they worked great. EVERYTHING is now way, way faster on my system (DP 450/2GB Sawtooth/10.4.8), from boot up to app launching to shutdown and everything in between

BUT YMMV !!!

dmetzcher · Nov 5, 2006, 02:16 PM

Originally Posted by bowwowman

Yes, to make a back-up/clone useful, it must be on a seperate drive. Having it on a partition of the same drive is essentially pointless, since 99.9% of major crashes are due to DRIVE failures, not the OS......

BTW, with reference to the swap file questions, I used the terminal commands at: Moving the swapfile in Mac OS X 10.4 (Tiger)

and they worked great. EVERYTHING is now way, way faster on my system (DP 450/2GB Sawtooth/10.4.8), from boot up to app launching to shutdown and everything in between

BUT YMMV !!!

Thanks for the link...reading it now.

Hal Itosis · Nov 5, 2006, 06:20 PM

Originally Posted by bowwowman

> Having it on a partition of the same drive is essentially pointless,
> since 99.9% of major crashes are due to DRIVE failures, not the OS.....

99.9%?!

Maybe in the land of "wha ha ha & wee hee hee."

bowwowman · Nov 7, 2006, 10:18 AM

Originally Posted by Hal Itosis

99.9%?!

Maybe in the land of "wha ha ha & wee hee hee."

Ok so maybe it's only 99%

At least for those of us who keep their installs/machines lean, clean & unhackyfied

dmetzcher · Nov 15, 2006, 12:13 AM

Originally Posted by chrismear

My gut feeling is that you'd get better performance having your system swap files and your application scratch files on separate physical disks, if you can.

I missed your meaning when I first read this some time ago. My Mac Pro is being shipped now from California, so I read this thread over (because I needed to remember how I'm setting it up), and it occurred to me that you meant that the swap files should be on one drive, while the scratch files for apps should be on another drive. Is that correct? It makes sense, but I'm not going to be able to do that right away (I simply don't have the cash right now to get another hard drive, and would rather spend that money on additional RAM). But, I could do this later, I suppose. It should be easy to change the location of the swap files, right? Eventually, I may want to move them again, but not initially.

In any case, thanks for your help, everyone. I'm getting the Mac Pro this Friday, so I should have a weekend of tasks to perform before everything is up and running the way I want it. This conversation was helpful.

Millennium · Nov 16, 2006, 08:16 AM

Generally speaking, there isn't much advantage to partitioning. You may have heard about benefits with putting the swap files on separate volumes, but they actually have to be on separate hard disks to receive most of the benefit: just using separate partitions isn't enough. Using partitions doesn't hurt anything, but it doesn't help either.