Raid 0 a power Mac G5

"As long as it is not your boot/Startup drive sure"

ostensibly... But if you started anew, zeroed the drive that came in the computer and the second drive you were going to set up the raid0 with... then did a clean install to the raid0 volume... couldn't you have your boot drive be the raid0?

"In my (unscientific) opinion, any perceived performance gain from RAID 0 on a G5 is purely a placebo effect."

My experience with my 2 10K Raptors in a stripe as boot is not a placebo effect what so ever.

Sure the OS, booting and opening apps can only go so fast the difference with a stripe pair internal Raptors and a single Raptor as a boot/app/itunes/bare bones home with files on a stock 7,200 RPM drive is minimal.

Where I see performance with my stripe is in

1: Duplicating large folders in half the time of a 7,200 RPM drive

2: Photoshop 7 & CS1 scratch (not needed for CS2 as Tiger overrides CS2's RAM limit)

3: Doing multiple intense drive I/O's from different programs

4: Opening larger folders of files displaying incredible fast.


My stripe has been up several months just fine, I have first zeroed each drive to reset the bad sector map before setting the stripe. Cloned from a external.

My main objective is to have a high drive I/O so I wouldn't have to worry ever again about performance or suffer from beach-balling. I get 185 MB p/s uncahced writes and since finding Deja Vu automatic cloning/backup software my worries about increased drive failure really have vanished.

My original Maxor drive failed on me one morning out of the blue, but my twin Raptors have been superb in their reliability.

If you clone occasionally and backup often like we all should, then really it's really not a concern if one has one drive or a stripe as boot if you think about it.

"...and I can confirm that this RAID 0 stripe set is no faster than a single drive. I will shortly be removing the Raptors and re-installing a single drive of higher capacity."

RAID O is indeed faster than a single drive, you just haven't run the tests or used something that is highly drive dependant like duplicating a 20GB folder.

Over time that larger capacity boot drive will make Mac OS X crawl as it's filled up and your OS is de-optimized, spread out all over the drive.



Click a pic to feel the awesome 30" • Clone your boot drive, read my how to post here

I believe the G5 can boot from a RAID.

I'm booted from a RAID 0 right now.

Is it possible to configure an internal hardware RAID0?

Tiger is quite capable of RAID 0 boot.

Mine been running boot RAID 0 ( the 2 internal SATA's connected to the stock controller, no card) for about 3 months now.

AFAIK 10.3 can boot from a software RAID1 but not from a RAID0.

10.4, I don't know if software RAID0 is bootable.

SCSI hardware RAID subsystems are bootable RAID 0, 1, 3, and 5.

Regards

Nicolas

I have two 400 GB SATA Hitachi drives in my G5 computer. I cloned my drive to an external FW drive, booted of the external drive and then used Disk Utility to make a RAID 0 on the two internal drives. I then cloned my system to the internal RAID 0 drive and set that as my boot drive. I backup to my external drive every week.

Running a software RAID0 as System/Boot drive is not that kind of use RAID0 is made for.

If one drive fails, your system is gone.

I prefer a single, fast disk as boot volume like a 15k SCSI drive.
Or a hardware RAID5.

IMHO the speed gain is not worth the troubles of a disk failure.

That's not the way Pro-users should use software RAID0, in no way.
If you have to make your money with such a system it could be end of your business.

RAID0 is for fast scratch subsystems, servers with backup (RAID10), or video pro's for capturing material.

But that's my position.

Regards

Nicolas

Daniel,

If you choose RAID0 for boot/system drive just 2 suggestions:

1. Do backups to an external- not RAIDed volume.
2. Use a third drive for your data if you know how put your user folder on that drive too. So, if your RAID crashes your data is more safe.

Regards

Nicolas

If one drive fails, your system is gone.

What if that one drive was your single system drive?

I don't feel RAID 0 is more reliable than single boot disks. But I don't feel it is less reliable, either. I hammer drives like crazy. I have found that I wear out single disks very quickly. RAIDs tend to last longer for me since the individual drives don't work nearly as hard.

Basically, I'm just saying that people shouldn't be afraid to do what they want. Mission critical should be backed up at all times whether it's RAID or not. Simple common sense should say that. Disks aren't 100%. Period. Back up your stuff. Then, do whatever the heck you want for performance or whatever the reason. Just keep a backup, and you won't have to worry or be afraid.

Hello Brett,

the point is most users are running without backups.

The more drives you are using in a stripped RAID aka RAID0 the higher risk of a failing drive. If you have one drive and it fails ok, some are using four or more drives than the risk will be fourfold.

IMHO if you double, triple or fourfold the risk of a data loss then please do your backups. Or put your data on an other non Raided volume.

Regards

Nicolas

Hi, Nicolas.

I guess I just see the drives and RAID and the hype of unreliability like this:

Worker: "You know, the chance that one of those four guys carrying that big box over there will fall is pretty high, since there are four of them. The chance that one will fall is 1 in 20, and the chance that one of those guys will fall is now 4 in 20 since there are four of them. That's 20% over 5%. And if one of those guys falls, the box will fall and the contents will break. What should we do?"

Corporate Manager of my company: "You're right. Let's just have one guy carry the box, and get rid of the other three. Not only will we save the box, but we'll save money."

I know it's dangerous, but really, I've had a better success rate with RAID 0 than I have JBOD or single disks. It seems I'm alone, maybe just lucky...

I have quite a bit of experience of running RAID stripe sets in Macs and I am pleased to be able to share the following with you.

Firstly, Tiger, Panther and IIRC Jaguar all boot from RAID 0.

It is a little tricky getting Jaguar to do it, but it is possible with a little workaround. If you install two brand new drives and run the Jaguar installer, it will be unable to create a RAID 0 set that you can install the OS on to. If however you install the OS on a third drive first, and then boot from that drive, you can use Disk Utility to create a RAID 0 set from the first two drives which the Jaguar installer will then be able to see and install on to.

Secondly, the general consensus is that there is no performance to be gained from RAID 0 in a G5. In fact, it is possible that your Mac could take a slight performance hit. The only real benefit from RAID 0 is the ability to create one large volume from two smaller drives. The downside, as others have noted, is the increased likelihood of volume failure.

I am currently running two WD Raptor 10Ks inside a G5 and they are configured as a RAID 0 stripe set. These are the fastest drives that money can buy – true Enterprise Class drives and I can confirm that this RAID 0 stripe set is no faster than a single drive. I will shortly be removing the Raptors and re-installing a single drive of higher capacity.

In my (unscientific) opinion, any perceived performance gain from RAID 0 on a G5 is purely a placebo effect.

I hope this helps

The only time I see a noticable increase in performance is when copying large files between drives. I have five 400 GB Hitachi drives in my G5 (using a Swift Data 200) with two drives in a RAID 0 using the Apple SATA controllers and the other 3 drive also in a RAID 0 using a Sonnet Tempo-X eSATA 4+4 PCI-X controller. Opening programs, saving Word/Excel files, etc don't show any noticable increase in speed. But when I copy files that are 50+ MB in size between drives or do a Secure Erase of a large file then the system screams, typically 70 to 100 MB/s sustained transfer speeds.