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Boot Leopard from PCIe SSD on G5 Quad

G5Swede

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Original poster
Dec 14, 2018
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I have been successful in booting different Linux distros off a PCIe SSD on my Quad by installing GRUB2 and /boot on a small SATA drive connected to the internal controller. Does anyone have any experience or know whether a similar solution could be possible for OSX Leopard? The SSD is AHCI and Leopard supports it natively but of course there is no Open Firmware support.

Thank you in advance and please excuse any errors in my English!
 
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LightBulbFun

macrumors 68020
Nov 17, 2013
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I would say the easiest way to go about doing what you describe is using the helper volume part of Xpostfacto

as thats exactly what its deigned for :)

(to boot OS X From say Firewire on a Mac that obviously does not support booting from firewire)

im happy to see someone try this out, as its been something I have theorised about in the past :)

which PCIe SSD are you using BTW? :)

(I wonder what your xbench scores are like on it :D )
 
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G5Swede

macrumors newbie
Original poster
Dec 14, 2018
4
2
I would say the easiest way to go about doing what you describe is using the helper volume part of Xpostfacto

as thats exactly what its deigned for :)

(to boot OS X From say Firewire on a Mac that obviously does not support booting from firewire)

im happy to see someone try this out, as its been something I have theorised about in the past :)

which PCIe SSD are you using BTW? :)

(I wonder what your xbench scores are like on it :D )

I am using a Samsung SM951 (PCIe AHCI, NOT NVMe and NOT SATA) and currently have an install of Leopard on a SATA disk which recognises the SSD out of the box. I don't have access to the Quad at the moment as I am out of town for the weekend but will run Xbench on it when I get home.

And the Xpostfacto idea is very good but I seem to recall XPF won't run on anything higher than Tiger? Or could one first install Tiger with Xpostfacto helper volume and then upgrade to Leopard in place? I've never even thought of using XPF on a G5 (as they all support up to Leopard natively of course) but this could be interesting... I will try some different things when I get back to the computer!

Thank you very much!
 
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LightBulbFun

macrumors 68020
Nov 17, 2013
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I am using a Samsung SM951 (PCIe AHCI, NOT NVMe and NOT SATA) and currently have an install of Leopard on a SATA disk which recognises the SSD out of the box. I don't have access to the Quad at the moment as I am out of town for the weekend but will run Xbench on it when I get home.

And the Xpostfacto idea is very good but I seem to recall XPF won't run on anything higher than Tiger? Or could one first install Tiger with Xpostfacto helper volume and then upgrade to Leopard in place? I've never even thought of using XPF on a G5 (as they all support up to Leopard natively of course) but this could be interesting... I will try some different things when I get back to the computer!

Thank you very much!

while xpostfacto does not officially support leopard, it will still open on leopard and function for the most part (as in I can install the patches/kexts it has and set boot arguments using it etc)

but I cant say I have tried the helper function under Leopard

you could also put a full install of 10.5.8 on a small disk then use the rd=diskXsX boot argument to redirect it to the SSD once the kernel starts loading :)
 
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MisterKeeks

macrumors 68000
Nov 15, 2012
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I have been successful in booting different Linux distros off a PCIe SSD on my Quad by installing GRUB2 and /boot on a small SATA drive connected to the internal controller. Does anyone have any experience or know whether a similar solution could be possible for OSX Leopard? The SSD is AHCI and Leopard supports it natively but of course there is no Open Firmware support.

Thank you in advance and please excuse any errors in my English!

Could you elaborate on how you got the linux distros to be boot from the PCIe SSD. I briefly attempted this a few weeks back - I had grub2 installed on a SATA hard drive. When I configured GRUB2 on Lubuntu (booted from an install on the SATA drive) it correctly picked up the Lubuntu install on the PCIe SSD, and the options showed in the boot menu - but if I selected them, it seemed to give me some open firmware-looking errors.

This is a very interesting topic and I'm eager to see where it all ends up. I was using an XP941 AHCI SSD FWIW.
 
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G5Swede

macrumors newbie
Original poster
Dec 14, 2018
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Could you elaborate on how you got the linux distros to be boot from the PCIe SSD. I briefly attempted this a few weeks back - I had grub2 installed on a SATA hard drive. When I configured GRUB2 on Lubuntu (booted from an install on the SATA drive) it correctly picked up the Lubuntu install on the PCIe SSD, and the options showed in the boot menu - but if I selected them, it seemed to give me some open firmware-looking errors.

This is a very interesting topic and I'm eager to see where it all ends up. I was using an XP941 AHCI SSD FWIW.

I have only done it with Debian and Gentoo but my solution was to put the entire /boot partition (with kernels, initrd) on the SATA disk but everything else on PCIe. With Debian you just have to do manual partitioning in the installer (easiest should be to just create /boot partition and bootstrap on SATA and make the PCIe disk one partition mounted at / but of course you can partition however you like). If you already have an install on the SATA disk that you want to keep I would put the kernel and initrd (and whatever else you may keep in /boot) in the /boot partition of your original install (highly recommend separate /boot partition) and configure GRUB to boot using those files and to use a partition on the SSD as root filesystem.
 
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MisterKeeks

macrumors 68000
Nov 15, 2012
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I have only done it with Debian and Gentoo but my solution was to put the entire /boot partition (with kernels, initrd) on the SATA disk but everything else on PCIe. With Debian you just have to do manual partitioning in the installer (easiest should be to just create /boot partition and bootstrap on SATA and make the PCIe disk one partition mounted at / but of course you can partition however you like). If you already have an install on the SATA disk that you want to keep I would put the kernel and initrd (and whatever else you may keep in /boot) in the /boot partition of your original install (highly recommend separate /boot partition) and configure GRUB to boot using those files and to use a partition on the SSD as root filesystem.

That’s a decent solution - ideally the install would be contained entirely on the SSD, with only GRUB2 on SATA? I assume doing so is unfortunately not possible with Open Firmware?

Also, I’ve noticed that earlier versions of Leopard kernel panic with the XP941 installed but after updating to 10.5.6 there are no issues - so maybe the AHCI driver was really in its infancy then.
[doublepost=1559939877][/doublepost]
while xpostfacto does not officially support leopard, it will still open on leopard and function for the most part (as in I can install the patches/kexts it has and set boot arguments using it etc)

but I cant say I have tried the helper function under Leopard

you could also put a full install of 10.5.8 on a small disk then use the rd=diskXsX boot argument to redirect it to the SSD once the kernel starts loading :)

I’ve never messed around with XPostFacto - wouldn’t it have to be able to recognize the PCIe SSD somehow? Or is there some other mechanism that I’m missing.
 
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DearthnVader

macrumors 65816
Dec 17, 2015
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Red Springs, NC
I’ve never messed around with XPostFacto - wouldn’t it have to be able to recognize the PCIe SSD somehow? Or is there some other mechanism that I’m missing.
The "helper disk" function of xPostfacto is just a redirect. It creates a copy of the kernel and extensions on a "supported" boot disc, once they are loaded into ram, you then have your AHCI/Firewire/USB drivers loaded, so OS X is able to mount the disc.

Then a simple redirect to the root file system on that disc.

The RD function was put into OS X to supported booting of RAID volumes that otherwise wouldn't be bootable.

You don't need Xpostfacto to do it, simple Open Firmware commands can be used, assuming you know how to set up the helper disc, but Xpostfacto makes the process much easier than resorting to the command line.
 
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G5Swede

macrumors newbie
Original poster
Dec 14, 2018
4
2
Sorry for the delay in posting; I have been busy at work but my holiday has started now so I have time for my hobbies again!

The Xpostfacto helper volume seems to have no effect; when I reboot it just boots back into the installation on the helper volume with all mounts identical. Using rd=disk0s3 (the identifier for the PCIe drive both on the installer disc and when booted to helper volume) also doesn't seem to do anything and when booting in verbose mode BSD root is specified as disk1s3 (the helper volume) with identical installs (10.5.6 directly from DVD, no updates or anything)

I had the thought of referencing the PCIe drive by Open Firmware path but I don't seem to be able to figure out how to specify the partition... Would anyone have any clue as to what I might be doing wrong?
[doublepost=1563117915][/doublepost]
That’s a decent solution - ideally the install would be contained entirely on the SSD, with only GRUB2 on SATA? I assume doing so is unfortunately not possible with Open Firmware?

Also, I’ve noticed that earlier versions of Leopard kernel panic with the XP941 installed but after updating to 10.5.6 there are no issues - so maybe the AHCI driver was really in its infancy then.
[doublepost=1559939877][/doublepost]

I’ve never messed around with XPostFacto - wouldn’t it have to be able to recognize the PCIe SSD somehow? Or is there some other mechanism that I’m missing.

I have done some research on getting GRUB2 to recognise volumes on the PCIe drive but as far as I understand that is impossible without firmware support (if anyone knows of a way to do this feel free to correct me as I would also be very interested).
 
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