G5 physical drive size limit, is there one?

orestes1984

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As per the the thread title I'm looking at getting another large hard drive for my G5 Xserve tomorrow. It address 1.5TB drives just fine, but I want to step up to a 3TB drive for it. Is this possible or will the G5 not address it?

I am running OS X 10.5 so a software disk size limit shouldn't be the issue, but I'm wondering whether there is a hardware limit.
 

SuperJudge

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Apr 2, 2008
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As per the the thread title I'm looking at getting another large hard drive for my G5 Xserve tomorrow. It address 1.5TB drives just fine, but I want to step up to a 3TB drive for it. Is this possible or will the G5 not address it?

I am running OS X 10.5 so a software disk size limit shouldn't be the issue, but I'm wondering whether there is a hardware limit.
There isn't a hardware limit, but there is a partitioning scheme limit. Make sure you use GPT for the new drive since APM can't go beyond 2TB because of it's addressing scheme.
 

Intell

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Jan 24, 2010
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The largest bootable internal drive you can put in it is 2TB. Anything bigger than that must be GUID formatted and PowerPC Macs cannot boot from a GUID partitioned drive.
 

orestes1984

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HUH, I've booted off of 3TB drives..

in APM..
I seem to be going around in circles of misinformation until I find someone else who has done this first :rolleyes: The magic number seems to go up every time someone else confirms it's possible :rolleyes: I think I'm better off just testing and finding out myself but I didn't want to buy a 3TB paperweight.
 

orestes1984

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If



then this doesn't matter, right?



You can always create 2TB and 1TB APM partitions on this drive if you'll want to boot off of it.
Yes... I should state that I have a 128gb boot SSD. The 3TB drive will be the third drive in my Xserve. I'm weighing up my options of getting another 1.5TB drive to stripe with the drive that is currently in the machine in a raid set then using the 3TB for backups.

Having an SSD in a G5 is a bit of a waste.
 

Intell

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Jan 24, 2010
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HUH, I've booted off of 3TB drives..

in APM..
Now that can't be done. Disk Utility complains that the drive is too big for the selected partition type and refuses to partition is with APM. The biggest accessible drive size when using the APM format is 2.2TB. It cannot be able bigger because APM lacks enough address blocks for it. While you can make one 2.2TB on a 3TB drive, the total overall size of all the partitions on a APM drive cannot exceed 2.2TB because the drive header doesn't have enough address blocks for all of the space.
 

GermanyChris

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Now that can't be done. Disk Utility complains that the drive is too big for the selected partition type and refuses to partition is with APM. The biggest accessible drive size when using the APM format is 2.2TB. It cannot be able bigger because APM lacks enough address blocks for it. While you can make one 2.2TB on a 3TB drive, the total overall size of all the partitions on a APM drive cannot exceed 2.2TB because the drive header doesn't have enough address blocks for all of the space.
The problem lies in the fact that I've done it..just like SATA 3 which I'm supposed to not be able to do.

Remember the thread about SATA 3 drives in the G5 and I showed the screen shot of my 3tb barracuda in drive bay b? That was my boot drive.
 

Intell

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The problem lies in the fact that I've done it..just like SATA 3 which I'm supposed to not be able to do.

Remember the thread about SATA 3 drives in the G5 and I showed the screen shot of my 3tb barracuda in drive bay b? That was my boot drive.
I never said SATA 3 drives don't work in G5's. I only said there have been many reports of incompatibility with them when they run in SATA 3 only mode. I've tried the 3TB APM just now and Disk Utility on Leopard on a G5 refused to make the partition any larger then 2.2TB. If I dragged it bigger, it'd just move right back to 2.2TB. It's a documented limitation of the APM format. Nothing can be done about it.
 

GermanyChris

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I never said SATA 3 drives don't work in G5's. I only said there have been many reports of incompatibility with them when they run in SATA 3 only mode. I've tried the 3TB APM just now and Disk Utility on Leopard on a G5 refused to make the partition any larger then 2.2TB. If I dragged it bigger, it'd just move right back to 2.2TB. It's a documented limitation of the APM format. Nothing can be done about it.
Right except I did it..
 

Intell

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Right except I did it..
Couldn't have. Disks using the Apple Partition Map are divided into logical blocks, with 512 bytes usually belonging to each block. Because APM allows 32 bits worth of logical blocks, the size of an APM formatted disk is limited to 2 TiB. This is how it's been since APM was first developed back in the 1980's. Even Apple's technical documentation notes this limitation: http://developer.apple.com/library/mac/#technotes/tn2166/_index.html

However, in recent years APM's limitations have been looming on the horizon. Specifically, APM is restricted to 32-bits worth of blocks. With a standard block size of 512 bytes, this translates to a maximum disk size of 2 TB. With the rate that hard disks are growing, it's easy to imagine a typical desktop computer shipping with more than 2 TB of storage in the next few years.
So unless you rewrote a closed source format from scratch to include 48 bits worth of blocks, you cannot format a drive with APM and have more than 2.2TB addressable on it.
 

jbarley

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Jul 1, 2006
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this thread is starting to remind me of another thread in the recent past about booting PPC from a USB drive.
Some were adamant that it could not be done without some firmware hacks, while others said they could boot, no problem.
My own experience in that case was thus...
my dual 1.8 boots from a usb drive,
my quad 2.5 refuses to boot from a usb drive,
go figure?
What GermanyChris states he can do, I tend to believe, why he can do it remains an unknown.

----------

Right except I did it..
Could you maybe post some screen shots of disk utility showing your partition and disk info, also maybe a shot of your boot drive (get info)?
 

666sheep

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Dec 7, 2009
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this thread is starting to remind me of another thread in the recent past about booting PPC from a USB drive.

[snip]

What GermanyChris states he can do, I tend to believe, why he can do it remains an unknown.
But in that thread there was many people positive vs negative experiences...

Here we have only one Chris claim vs logic and mathematics ;)

BTW, Chris, did you find that "magic" Core Player version yet? Could you share if so?
 

GermanyChris

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Jul 3, 2011
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this thread is starting to remind me of another thread in the recent past about booting PPC from a USB drive.
Some were adamant that it could not be done without some firmware hacks, while others said they could boot, no problem.
My own experience in that case was thus...
my dual 1.8 boots from a usb drive,
my quad 2.5 refuses to boot from a usb drive,
go figure?
What GermanyChris states he can do, I tend to believe, why he can do it remains an unknown.

----------


Could you maybe post some screen shots of disk utility showing your partition and disk info, also maybe a shot of your boot drive (get info)?
it's in the Mac Pro now.

I did post limited screen shots in the other thread

----------

But in that thread there was people positive vs negative experiences...

Here we have only one Chris claim vs logic and mathematics ;)

BTW, Chris, did you find that "magic" Core Player version yet? Could you share if so?
I said I'd share with Intell not everyone..

Chris got a 2000 euro bill from the German government for "sharing" in February.

It's just what it is..
 

Intell

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Jan 24, 2010
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this thread is starting to remind me of another thread in the recent past about booting PPC from a USB drive.
Some were adamant that it could not be done without some firmware hacks, while others said they could boot, no problem.
My own experience in that case was thus...
my dual 1.8 boots from a usb drive,
my quad 2.5 refuses to boot from a usb drive,
go figure?
What GermanyChris states he can do, I tend to believe, why he can do it remains an unknown.
In that thread it there was one person saying it couldn't be done, even though Apple's documentation said it could. Here we have the reverse. One person says it can be done, but Apple's documentation says it can't.

I never got that cracked CorePlayer either. But I guess that must be because it doesn't exist.
 

orestes1984

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LET ME CLARIFY THIS FOR YOU

I do not care if the drive boots or not, I have a boot drive. Please stop hijacking this thread with your pointless arguments :rolleyes:
 

Intell

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Jan 24, 2010
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I do not care if the drive boots or not, I have a boot drive. Please stop hijacking this thread with your pointless arguments :rolleyes:
Of course back on thread title's topic. Yes there is a physical drive size limit. It must be no bigger than 1.028x5.787x4 inches. Any bigger than that, and it'd have to go in the optical drive bay instead of the hard drive bay.
 

jbarley

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Jul 1, 2006
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LET ME CLARIFY THIS FOR YOU

I do not care if the drive boots or not, I have a boot drive. Please stop hijacking this thread with your pointless arguments :rolleyes:
I think this juvenile outburst was uncalled for. We all understand that your question was answered to your satisfaction several posts earlier.
But I'd like to believe that you are not so selfish that you'd deny the rest of the PPC users in the world the benefit of knowing the pros-cons of installing a HDD larger then 2GB.
 
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