RAID 0 on MacPro 08

[Pam2611]

Hi! I just ordered a MacPro configuration. Since HDD in the original configuration isn't so great, i was thinking to buy 2x WD Raptor 150 Gb and connecting them in a RAID 0 field, and installing OS X and applications. Is this posibile without the 800$ RAID card? Something like a software RAID... This computer would be used in a quick printshop (Adobe CS3, Autodesk, Office Suite, Corel,....) and the important thing is quick opening of different programs, and saveing large files 2Gb+.

If it's posibbile to make a software RAID would the configuration be faster then a single Raptor or Samsung's Spinpoint F1? The capacity of the primary drive is not a problem im only interested in their (his) speed, so i treat 2x 150gb and F1 750gb the same.

THANKS!!

 

[WildPalms]

Firstly, Raid 0 is not redundant. If you lose one disk, you lose all data on all the disks participating in the array. The predominant approach to system volumes is to mirror them for redundancy.

However, since it is speed you are going for, and there are different approaches (e.g. storing the applications on a different striped volume separate to the OS) so as long as you have backups performed regularly, you can install two hard drives, boot from the DVD, setup the mirror and then install onto that newly created volume.

It will be faster than a single drive to a point, until the bus or the controller are data saturated.

 

[bigbossbmb]

You'd be better off with just get a good 7200rpm drive as the system disk. The Samsung F1 1TB drives are even faster than the Raptors. Get two of those, don't RAID them and use the second as a media storage drive. A third drive (doesn't need to be big, just fairly quick) would be good to get for use as a scratch disk.

 

[Pressure]

Don't let them scare you away from RAID-0. It works like a charm but you need to find a backup solution.

 

[Toups]

Raid 5

Raid 5 is also a valid option for those looking for speed and the ability to survive a single drive failure, and when you use 7200RPM SATAII drives you get transfer rates around 250-275MBps which is about 2-2.5 times faster than a single SATAII drive, and if you lose a drive, just replace it and it will automatically rebuild the lost data for you.

As far as the one drive for this, one for that strategy, if you use a large raid, the recommendation is to setup partitions not separate drives for cost effectiveness. Keep in mind that RAID 5, while fault tolerant is NO substitution for a sound external backup strategy. Also, in RAID 5, all of the drives need to be of the same size and interface type, i.e. SATAI or SATAII to maximize throughput.

 

[davidwsica]

Raid 5 is also a valid option for those looking for speed and the ability to survive a single drive failure, and when you use 7200RPM SATAII drives you get transfer rates around 250-275MBps which is about 2-2.5 times faster than a single SATAII drive, and if you lose a drive, just replace it and it will automatically rebuild the lost data for you.

As far as the one drive for this, one for that strategy, if you use a large raid, the recommendation is to setup partitions not separate drives for cost effectiveness. Keep in mind that RAID 5, while fault tolerant is NO substitution for a sound external backup strategy. Also, in RAID 5, all of the drives need to be of the same size and interface type, i.e. SATAI or SATAII to maximize throughput.

That's a good option though it requires the ~$800 RAID card (i.e. not implemented by Apple's Software RAID, or SoftRAID).

 

[Toups]

That's a good option though it requires the ~$800 RAID card (i.e. not implemented by Apple's Software RAID, or SoftRAID).

True, but with software raid, if you lose the OS or have a drive hiccup on the system drive, all is lost. Also, typically there is a 20% drop in performance of Raid for software vs a hardware Raid which directly relates to the additional processor overhead requirements to calculate the Raid operations, albeit in an 8-core system this would be minimal.

 

[davidwsica]

True, but with software raid, if you lose the OS or have a drive hiccup on the system drive, all is lost. Also, typically there is a 20% drop in performance of Raid for software vs a hardware Raid which directly relates to the additional processor overhead requirements to calculate the Raid operations, albeit in an 8-core system this would be minimal.

No doubt, I would rather have hardware RAID. I'm just pointing out that your $2799 Mac Pro jumps ~30% to add the RAID card. I'm personally trying to decide whether that's in my budget or settle for software RAID for now.

 

[Toups]

I agree completely, if you are looking to double drive performance, software RAID is a great option, hardware would be the "enterprise" vs "home" option.

For my system, I ordered the base config with the RAID card and will be adding 1tb drives myself as well as 8GB RAM saving over 2500 from what apple charges.
FWIW, This would give you a maxed out system with 4TB (3TB with RAID) and 8GB of ram for about $5,000 which is about 4k less than then next closes windows/linux server

 

[Pam2611]

So how do i make this sofware RAID? As you probably noticed this is my first mac so... Since i want to install OSX on a RAID array, it's not posibile to use OS level software before the instalation of the OSX is finished. Can i make a RAID 0 during the OSX instalation or do i need to install OSX on a single drive then add the second and use the RAID software.

With hardware RAID it's realy simple, 1. you make the array thru a application instaled on your RAID card (or MBs RAID controler) and 2. install WinXP (every 6 months

 

[Toups]

So how do i make this sofware RAID? As you probably noticed this is my first mac so... Since i want to install OSX on a RAID array, it's not posibile to use OS level software before the instalation of the OSX is finished. Can i make a RAID 0 during the OSX instalation or do i need to install OSX on a single drive then add the second and use the RAID software.

With hardware RAID it's realy simple, 1. you make the array thru a application instaled on your RAID card (or MBs RAID controler) and 2. install WinXP (every 6 months

You cannot install OSX on a software RAID, as OSX is used to setup the RAID on the additional disk. This would mean you have at least 3 drives, the first would contain OSX, the 2nd and 3rd would be used for the RAID. I know its not the "ideal" scenario, but then again that is why I ordered the RAID card when I purchased my Mac Pro, since I figured 2-2.5x increase in drive performance and single drive fault tolerance with RAID 5 was worth the investment.

*** RAID is NOT a replacement for a sound backup strategy, but properly used, can avoid having to refer to backup as often and maximize throughput.

 

[davidwsica]

You cannot install OSX on a software RAID, as OSX is used to setup the RAID on the additional disk. This would mean you have at least 3 drives, the first would contain OSX, the 2nd and 3rd would be used for the RAID. I know its not the "ideal" scenario, but then again that is why I ordered the RAID card when I purchased my Mac Pro, since I figured 2-2.5x increase in drive performance and single drive fault tolerance with RAID 5 was worth the investment.

*** RAID is NOT a replacement for a sound backup strategy, but properly used, can avoid having to refer to backup as often and maximize throughput.

NOT TRUE. I just bought my new Mac Pro yesterday. I brought it home and stuck 2 additional 320GB drives in it. Then I booted from the Install DVD, ran Disk Utility and setup the 3-drive RAID 0 array, then installed OS X on it. No problem at all.

 

[Toups]

Looks like they may have updated the boot loader to allow OSX to load on a software RAID, but be warned ANY drive error/failure in the array will wipe out the ENTIRE array.

BAKCUP BACKUP BACKUP!!!


FYI, each time you add a drive to a RAID 0 array to decrease the MTBF and increase the odds of failure; i.e. a drive has an error rate of .002% each time you add a similar drive you increase the likelyhood of failure. Two drives in this scenario would error rate at .004%, three drives at .008%, four at .016% and so on.