Spliting OS

CharlieJ

CharlieJ

R.I.P bobw
Can I Instead of getting a 80GB HD, I Get 40 GB + 40 GB and half the OS between the drives so it loads quicker?
Will it be much faster?
Will it be slower?
How much will it cost?
Will 40GB + 40GB cost more than 1 80GB?
Would my computer get hotter?
Would my computer get louder?

Thank you in advance,
Charlie
 
Do you mean you want to split the Mac OS X installation between two partitions or 2 hard drives?

Mac OS X and iLife applications have to be in the startup volume. In one partition.
 
I think he means to have two actual harddrives and to put some things of the OS on one, and other parts on the second drive. In order to speed things up.

The answer to that would be: No. But if you have two same-size harddrives, you could create a RAID so that the drives appear as one volume. _This_ would increase performance, maybe.
 
RAID-0 is 2 or more drives linked together and formatted to appear as one drive, when in actual fact, it's many. using a method called 'striping', it distributes the data evenly across the drives. by having the double (or triple, or quadruple etc, depending on the number of drives) bandwidth acheived with the mutiple cables, read and write times can dramatically improve.

however, although macos x can do all this for you, the amount of resources taken up by the computer trying to work out where all this data is going, striping it over the different drives usually results in an overall performance hit, slowing the computer down in other ways (CPU and RAM).

to solve this, you need a dedicated RAID server, which would be a serperate box full of harddrives sat next to your mac, and hooked up via special I/O ports in a dedicated PCI-card. this would be dedicated in working out all the data calculations.

www.apple.com/xserve/raid

the other problem is that if one drive fails, all the data is pretty much useless, meaning if one goes, they all go. different RAID solutions offer different options. for example, RAID1 is two drives mirroring each other, a perfect back up, but somewhat slower than just one drive.

http://www.adaptec.com/worldwide/pr...guage=English+US&prodkey=RAID_level_compar_wp
 
Then again, I guess he was talking about re-using old hardware, not thinking about buying a RAID or anything. ;)
 
Lt Major Burns said:
RAID-0 is 2 or more drives linked together and formatted to appear as one drive, when in actual fact, it's many. using a method called 'striping', it distributes the data evenly across the drives. by having the double (or triple, or quadruple etc, depending on the number of drives) bandwidth acheived with the mutiple cables, read and write times can dramatically improve.

however, although macos x can do all this for you, the amount of resources taken up by the computer trying to work out where all this data is going, striping it over the different drives usually results in an overall performance hit, slowing the computer down in other ways (CPU and RAM).

the other problem is that if one drive fails, all the data is pretty much useless, meaning if one goes, they all go. different RAID solutions offer different options. for example, RAID1 is two drives mirroring each other, a perfect back up, but somewhat slower than just one drive.
Click to expand...

You are right on some: Raid-0 is faster and it makes several disks look like one. Also it is adds probability that there will be problems with disk. But, why would it slow things down? OS (x in this case) has to anyhow decide where to put data, so it does not slow much when splitting the data to two disks.

Raid-1 is more robust, since instead of writing the data to one disk, it is written to two. If then one disk breaks, it is quite small possibility that the other one breaks also before you fixes it. But: it is not slower than one disk. Actually reading is almost twice as fast, since each other block can be read from a different disk. This needs controller that supports this stuff, but I have such
(on my Linux PC) and it works. And yes: say after me: RAID-1 IS NOT BACKUP, use separate backup disk, CD or whatever.

(Best Raid is actually Raid-10, since it has speed of the Raid-0 and security of Raid-1. Some cheaper controllers have Raid-0,1, which is a little bit similar but not the same.)
 
fryke said:
Then again, I guess he was talking about re-using old hardware, not thinking about buying a RAID or anything. ;)
Click to expand...

What do you mean "Using old hardware"?
Are you saying im not going to get a new drive but pull a old one out of my granddads old pc?

I will be buying brand new hard-drives
 
artov said:
You are right on some: Raid-0 is faster and it makes several disks look like one. Also it is adds probability that there will be problems with disk. But, why would it slow things down? OS (x in this case) has to anyhow decide where to put data, so it does not slow much when splitting the data to two disks.

Raid-1 is more robust, since instead of writing the data to one disk, it is written to two. If then one disk breaks, it is quite small possibility that the other one breaks also before you fixes it. But: it is not slower than one disk. Actually reading is almost twice as fast, since each other block can be read from a different disk. This needs controller that supports this stuff, but I have such
(on my Linux PC) and it works. And yes: say after me: RAID-1 IS NOT BACKUP, use separate backup disk, CD or whatever.

(Best Raid is actually Raid-10, since it has speed of the Raid-0 and security of Raid-1. Some cheaper controllers have Raid-0,1, which is a little bit similar but not the same.)
Click to expand...

it's the controller that is key, isn't it? a hardware controller (like in a seperate RAID box) is needed to reap the full benefits, using the os x software controller is apparently not that good. i have no experience in this though.
 
Lt Major Burns said:
it's the controller that is key, isn't it? a hardware controller (like in a seperate RAID box) is needed to reap the full benefits, using the os x software controller is apparently not that good. i have no experience in this though.
Click to expand...

Yes, without controller Raid1 is as slow or slower than a single disk.
 
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