[mac128k-1984]

I see over at the apple discussions forum quite a lot of people wanting to use RAID on their new mac pros. Specifically 0+1. While I can see getting a speed bump from using raid 0 even when its software based. I'm not seeing the benefits of raid 1 insofar as that the overhead for the mirror may offset the performance gain of stripping.

Since I really am not that familiar with raid nor have I used it on my macs, perhaps someone more knowledgable can chime in. Such as how much faster would stripping a 7500rpm drive really be? what type of overhead would adding raid 1 do to performance etc.

[webmonkie]

Does the G5 DP machine support RAID? If not what can anyone advice me for a RAID solution in a MAC G5 DP machine.

[SciFrog]

I guess you have never lost a hard drive if you don't care about backup...

[mac128k-1984]

Originally Posted by SciFrog

I guess you have never lost a hard drive if you don't care about backup...

I'm not asking about backups and yes I care about them. Perhaps you should reread what I was posted.

I'm asking if the overhead of raid 1 reduces the performance gains of raid 0 since the raid solution is software based which means it is not as efficient as hardware based raid solutions.

[OreoCookie]

Originally Posted by webmonkie

Does the G5 DP machine support RAID? If not what can anyone advice me for a RAID solution in a MAC G5 DP machine.

Yes.

Originally Posted by mac128k-1984

I'm asking if the overhead of raid 1 reduces the performance gains of raid 0 since the raid solution is software based which means it is not as efficient as hardware based raid solutions.

Yes, it will. But not because it is software-based, but because of the principle behind it.

[mac128k-1984]

Originally Posted by OreoCookie

Yes.

Yes, it will. But not because it is software-based, but because of the principle behind it.

Thanks for the claification.

While I'm happy with the performance of my MacPro, stripping the drives will eke out even more speed but I don't particularly care for the risk of spreading the data across two drives. now since some (all?) of the performance gains will be reduced by mirroring the drives it doesn't seem to be worth the cost of adding three more drives. (I have 1 250, I'll need three more).

[OreoCookie]

That clearly depends on the gains that you think are worth it.
The overhead is not particularly big, so your performance loss is pretty much marginal. (Only writing is slower, because both drives have to write the data simultaneously.)

[mac128k-1984]

Its more out of curosity. I think the MacPro is pretty quick and while I could speed things up by using raid 0, I have no real clear cut desire to spend the money on extra drives to do this.

It seems to be a very popular subject over at the apple discussion forums. Some people are doing because of audio and video work but it seems the majority are wanting to do it (and asking how) just because the macpro can hold 4 drives and they figure why not.

[Leonard]

It's a popular subject on the Mac Pro, because with all the fast memory and CPU, the bottleneck is now the hard drive. There are only two ways to speed up the HD, RAID or a faster HD like the raptors. Barefeats actually show quite a gain in speed in a few operations Best boot drive for the Mac Pro? while some operations don't see much of an increase.

[mduell]

Originally Posted by OreoCookie

That clearly depends on the gains that you think are worth it.
The overhead is not particularly big, so your performance loss is pretty much marginal. (Only writing is slower, because both drives have to write the data simultaneously.)

With the drives on seperate channels, why is that slower?

[OreoCookie]

It's got nothing to do with the drives using the same or different channels.

AFAIK write access is slower than a single drive, because the drives need to write synchronously -- which is unnecessary for reading data.