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View Full Version : How will RAID help/hurt LW?



Ge4-ce
10-16-2003, 06:03 AM
Hi, I was thinking something lately.. How would a raidconfiguration help speed up your Mac and especially LW...

Ofcourse I do not mean the mirror mode, but the other one, for greater speed.

Does anyone has experience with this?

ps: Raid on Mac I mean.

Lynx3d
10-16-2003, 07:00 AM
Ofcourse I do not mean the mirror mode, but the other one, for greater speed.

"The other one"?
There are 8 basic RAID levels (from 0, which you probably mean and strctly speaking is no RAID, up to 7) plus combinations of different levels.

A small overview:
http://www.anandtech.com/guides/viewfaq.html?i=110

So I assume you have a controller that only supports RAID0 and 1 (striping and mirroring).
First, i would NEVER use RAID0 (striping) for my Lightwave data, because as i said before, it's not really RAID wich mean REDUNDAND array of indepent (or inexpendive) disks, and striping is everything but redundand. If one disk fails your data is lost, and with two HDs the risk is twice as high as with a single HD.

Besides that, where is Lightwave disk limited? Those maybe 1-5MB object files? Not even Lightwave itself takes longer than a few seconds to load. Perhaps some very large texture files take a few seconds, but they are only loaded once.
You can use it to speed up the system/program startup, improve performance for video editing or saving large photoshop files and the like, but i doubt you will notice any difference in Lightwave most of the time. And don't put very important data on it unless you have a backup.

As mentioned, there are combinations of RAID levels, so you could use RAID 1+0 (often called RAID10), but that needs a total of 4 disks and 50% of the space is used for mirroring. But it's very fast and very secure (but still RAID doesn't substitute backups).

More expensive controler-wise would be RAID5, it needs at least 3 disks, and 1/3 of space is used for parity data. But, it has no great write performance and read performance won't match striping too in most cases.

The whole RAID considerations are not really platform dependant btw. For more infos you might want to check the videotoaster forums, that's where the RAID gets used a lot...and the experts are :)

Ge4-ce
10-16-2003, 08:59 AM
Well.. I assume I can go with RAID 1! Mirroring! The reading performance is better wich allows faster booting, faster programlauches, faster filereading (often work with 600MB photoshops and bigger) And for lightwave, it is not a drawback!

And at the same time! I do have a little bit more safety about my data! As you said, a good backup is never replaceable, but when using raid 1 (mirroring) you should be safer.

mlinde
10-16-2003, 10:20 AM
He Ge-4ce. There is a recent discussion of RAID on Mac OSX over in xlr8yourmac. Here's the url: http://www.xlr8yourmac.com/OSX/OSX_RAIDvsIDE_Card_RAID.html

IMHO, the only thing RAID will do to speed up lightwave is in reading image sequences for surfaces or writing images to the disk. However, for general video/animation production (compositing, editing footage, etc.) RAID arrays are faster than a single disk for data I/O. It would help with your photoshop work. And yes, you want to look at RAID 0 or 1, even though 0 isn't redundant or recoverable, it is the fastest disk array structure.

Ge4-ce
10-16-2003, 12:11 PM
I also discoverd this: You cannot use your main harddrive (bootdisk) for raid! 'It cannot be used on the startup disk' is mentioned in the Mac help. My question is then: since you can only put 2 internal disks into a new G5, you have to go external with your raid! Bummer :( I almost figured it out.. Wanted to install 2 250GB harddrives in my G5 in January.. Put them in raid and gain some speed on those large files.. Externals are too expensive and not as practical.. guess it's going to be a single then..

jdavidbakr
10-16-2003, 12:57 PM
I'm sure this isn't recommended, but... we have in three of our dual-800's two additional internal drives. Up by the Superdrive there is a second IDE port on the ribbon cable (where you could put an internal floppy or something) that we slapped a drive on and then tie-wrapped it to the SuperDrive. Have had this setup for about 3 years now and haven't had any problems with it. One of the computers has this drive stripped together with the second drive (down by the main drive).

mlinde
10-16-2003, 02:07 PM
In the PowerMac G4 (quicksilver) there is space at the bottom of the case for an additional drive (or two, with a bracket) for a total of 4 drives at the bottom of the case (the boot drive is already there). I don't know which model introduced this, and which stopped having it though.

As for the G5, external RAID systems aren't that expensive, and since you needed a PCI card for it anyway, the only drawback is the desk space.

Medea products (http://www.medea.com/flash2/CFML/ModelPricing/ModelPricing-US-CAN.cfm#FireWire)
Micronet products (http://www.micronet.com/products/index.html)
Firewire direct (http://www.firewiredirect.com/firewire/products/RAID.shtml)

You could also build your own RAID cabinets, or buy an x-serve RAID kit :)

Lynx3d
10-16-2003, 02:21 PM
Er well that RAID1 is not always faster than a single drive, actually i have yet to find an IDE RAID controller that supports some load balancing, so it will behave like a single disk... :(
It's really hard to find out something about that, no one seems to be interested in RAID1...it's mainly 0, 5 or 10 in all reviews etc., so if there's an expert...HELP! :)

I don't know if OSX hast software-RAID, but usually you can't boot from that anyway.
And AFAIK the benefit of RAID1 with such balancing optimizations only really shows when multiple files get requested (when there is a "queue"), a single file can not be directly read by both disks since it's not striped, it's fragments could be everywhere.

Ge4-ce
10-16-2003, 03:42 PM
I'm more and more convinced that My Mac will be one without RAID.. :) I thought this was all way simpler than it is.. I figured out, put in just another harddrive, put them in raid-mode, and whieeehaaa.. faster system.. Nope, seems not since you cannot boot from standard MacOS X raid.. Then it becomes more costly.. New harddrives are way faster than old ones anyway.. ( I hope..)

Going to invest that money in extra RAM or a 3Dlabs card (see other thread ;) )