Can you RAID a G5???

mekhanes · August 27, 2003 3:58PM

I'm surprised that I have heard no mention of this issue, but the G5 only has room for 2 drives max... Ok, so how do you stripe a RAID? It would take 3 drives (one for boot two for RAID) to do it. What gives?

Can Panther boot from a RAID? Did Apple have a brain fart?

jll · August 27, 2003 4:02PM

Not this again!

rabidpenguin · August 27, 2003 5:25PM

Quote:

Up to 500GB of internal storage

The Power Mac G5 has two Serial ATA hard drive bays for up to 500GB of fast internal mass storage ? ideal for video, audio and high-resolution graphics. Built-in software RAID allows you to stripe the two drives for increased performance or mirror them for high reliability. And it?s easy to add storage as your needs grow. Single-drive systems come with the cabling to connect a second hard drive, and the easy-to-open side panel lets you insert a new drive yourself. Want massive system storage? Just use a Fibre Channel PCI card to connect to Xserve RAID, Apple?s high-performance storage system.

beigeuser · August 27, 2003 6:35PM

I am confused here. I thought that you cannot boot up from a software RAID volume. You can find this information if you do a search for RAID in the disk utilities help center (under Jaguar).

But according to rabidpenguins post, Apple seems to encourage RAIDing the two internal drives. How do you boot? Does the G5 have some kind of firmware that allows booting from a software RAID volume? Or does Apple assume that you will boot off of an external volume?

npynenberg · August 27, 2003 6:44PM

I have 2 drives soft raid'ed' in a Dual processor G4 tower. It boots fine.

August 27, 2003 7:54PM

Quote:

Originally posted by Mekhanes

I'm surprised that I have heard no mention of this issue, but the G5 only has room for 2 drives max...

Phew....stop it...you're killing me....

cory bauer · August 27, 2003 8:29PM

This is my idea for getting around the 2 Drive limit. Please someone come forward and let me know if this wouldn't work.

? Install two 250GB Drives.

? Partition each into a 220GB and 30GB part, giving you two 220GB drives and two 30GB Drives.

? RAID the 220GB partitions together to become 440GB, and RAID the 30GB Partitions together to become 60GB.

? Install your System software and Applications on the 60GB RAID, and keep all of your media on the 220GB RAID.

Any problem with that? If so, any other suggestions?

socrates · August 28, 2003 6:53AM

Quote:

? RAID the 220GB partitions together to become 440GB, and RAID the 30GB Partitions together to become 60GB.

? Install your System software and Applications on the 60GB RAID, and keep all of your media on the 220GB RAID.

Erm... you seem to be confusing two types of RAID. Are you suggesting striping the two 220GB partitions to make a fast 440GB, or mirroring them to make a reliable 220GB?

And how does this solve the problem (assuming there is one, which has already been denied by npynenberg) since you will now still have your system installed on a striped 60GB raid array?

perhaps you meant to stripe the 220GB sections to make 440GB, and mirror the two 30GB sections so that they would form a 30GB drive for the system, assuming that whatever problems there are with striping a system volume do not apply to mirroring it (which would make sense, since on a mirrored drive setup the whole data set is present on both drives if I remember right).

spotcatbug · August 28, 2003 7:04AM

You can boot Disk Utility RAID'ed volumes - into OS X only. People didn't like to do it before, because they wanted to boot into 9 every now and then. Now that modern Macs (G5 included) can't boot 9 anyway, the whole thing is moot. RAID away!

barto · August 28, 2003 7:07AM

1) You can partition disks to create more than you have, with less performance. You can RAID disks to create less than you have, with more performance. You cannot however do both.

2) Boot from FireWire. Some production environments do this, makes fixing broken installations a breeze (unplug disk A, plugin disk

3) Even then, RAIDs are uncommon. If you need the maximum disk performance, you go with an external solution like an Xserve RAID, or just buy something performance oriented like an Xserve.

Barto

markiv · August 28, 2003 8:42AM

I just want speed, I think Stripe would be my option. I have never had a computer with multiple hard drives before. Can I stripe the hard drives without partitioning them. Second what's the difference between Hardware RAID and RAID done throught software. Would I not require a RAID card to perform RAID. I want to RAID for speed and not for backup etc. Please advice.

cory bauer · August 28, 2003 11:28AM

I'd like to point out that, from my understanding, the only reason the "System on one drive, Media on another" idea exists is because 1.) writing large media files to your system drive will effect performance and 2.) if you keep it all in one place and your hard drive dies you not only lose your media but you lose your computer system as well. Ya know, every day people are editing dv video with iMovie to their system drives just fine. With the speed of the SATA drives and a G5, the performance hit of having your system and media on the same hard drive my be negligible. The answer we're all seeking may simply be to get two 250GB Drives, stripe them into 500GB, and call it a day. The performance gains of the SATA RAID most likely outweighs the performance hit of the Media and system sharing the same drives.

Quote:

Originally posted by Socrates

Erm... you seem to be confusing two types of RAID. Are you suggesting striping the two 220GB partitions to make a fast 440GB, or mirroring them to make a reliable 220GB?

Either/Or. It would depend if the user wanted a constant backup (Mirror) or as many GB as they could get. Although you're technically putting your system and your media on the same drives, since they are partitioned it's less of an issue. For most people, ordering the 160GB drive (the smallest available) with their G5 for their system and applications and adding a 250GB drive for their media would be ideal. Those SATA drives will be plenty fast without any kind of RAID going on.

Quote:

Originally posted by Socrates

perhaps you meant to stripe the 220GB sections to make 440GB, and mirror the two 30GB sections so that they would form a 30GB drive for the system, assuming that whatever problems there are with striping a system volume do not apply to mirroring it (which would make sense, since on a mirrored drive setup the whole data set is present on both drives if I remember right).

That works too. But I don't think 30 GB is enough these days for a system drive. If you install all of the included media for Soundtrack and Livetype (included with FCP4) you're looking at 15GB right there.

So, what you do is you install two 250GB drives, break them each into a large and small partition, and RAID the small partitions together and the large partitions together, essentially giving you a small drive and a big drive. Use the big drive for media, and use the small drive for everything else. Whether Disk Utility will allow you to RAID partitions together I am not sure. If Apple had just made room for one more Hard Drive this would all be so much easier. *sigh*

markiv

You can certainly stripe drives without partitioning them. Drop in two identical hard drives, open up Disk Utility and create a Stripe RAID. It's that simple. No additional hardware is required, and although hardware RAID cards are available, they are highly overrated and not worth the money, in my opinion. Software RAID's used to suck, but today they sometimes are even faster than Hardware RAIDs.

markiv · August 28, 2003 2:00PM

Thanks for the advice Cory. I bought an 80GB hard drive identical to the one in PowerMac G5. Both being identical in size I think I should be able to RAID them. I have one more question, how much performance increment should I expect doing Software RAID. Thanks a lot.

ghost_user_name · August 28, 2003 2:31PM

Moving to Current Hardware.

dasein-geist · August 28, 2003 7:33PM

markiv,

Check out http://www.storagereview.com/

Your question comes up often, in the discussion forums.

willywalloo · August 29, 2003 9:47AM

Quote:

Originally posted by Barto

1) You can partition disks to create more than you have, with less performance. You can RAID disks to create less than you have, with more performance. You cannot however do both.

Barto

Are you sure you have your typing fingers screwed on right?

This is how I remember it to be:

You can partition disks to create more than you have, with MORE performance. You can RAID disks to create less than you have, with LESS performance. You cannot however do both.

The reason backing this: if you partition (RAID 0) two drives together as for more space, one bit, or alotted amount, is sent to one drive, and while that drive is writing, the other drive is sent the next "bit" of data. So you can imagine the speed increase of RAIDING two drives as one with this format, RAID 0. (so you get total space utilized with greater speed)

RAID 1 is usually slower, and that's why people require fast hard drives, especially on the server end, because the RAID controller sends the same bits to two or more hard drives. If one drive fails, then you put another in and keep on chugg'n. In some systems all data from the good HD is then copied onto the new HD and the RAID resumes. (so you only see half the space, but have a high level of drive integrity)

RAID 3 is awesome because it takes the two RAID's above and uses the best from each. You get drive integrity (quick backing up from RAID 1) with speed. This takes a minimum of 3 drives. The way in which is works is more complicated. (so you have only the space of the two hard drives, with a parity drive that is not scene, but you get drive integrity with speed increase)

hope this helps.

-walloo.

gargoyle · August 29, 2003 10:04AM

Some of you seem to be getting confused with disks and partitions. You can RAID your disks and then split them up into partitions, eg. have 2x250G drives using RAID 0 and 1 big 500G partition. This would normally give a speed increase, as the software will write/read from both disks at the same time - but no redundancy.

Some software RAID implementations will let you RAID partitions, but at the end of the day - this does not give you the performance or redundancy you associate with the name RAID. IMO, they should actually call this type of partition setup something else.

Hope this helps.

Edit:

BAck to original question, there should not be a problem booting into a RAID setup as all the RAID information should be on ALL the disks.

matsu · August 29, 2003 10:55AM

Apple hates you, you're no pro enough to afford offline storage, go get an iMac.

Can you RAID a G5???

Comments