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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!
 

LightBulbFun

macrumors 68030
Nov 17, 2013
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London UK
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 )
 

G5Swede

macrumors newbie
Original poster
Dec 14, 2018
4
7
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!
 

LightBulbFun

macrumors 68030
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 :)
 

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.
 

G5Swede

macrumors newbie
Original poster
Dec 14, 2018
4
7
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.
 

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 68000
Dec 17, 2015
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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.
 

G5Swede

macrumors newbie
Original poster
Dec 14, 2018
4
7
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).
 

flyproductions

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Jan 17, 2014
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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.
So a little late, after two years, to confirm this. But right! The XPostFacto-method just doesn't work!

I did the same: tried to boot of one of these nice working but sadly not booting "unknown AHCI standard controllers" via XPF's "helper disk". And it just didn't! Instead it fully booted of the "helper" itself.

So after all, the fastest Mac OS-bootable "solution" for a G5 seems to be, what i have at the moment (temporary): A Raid 0 of two SSDs connected to the G5's onboard SATA I ports. Temporary, as i know it is in general not a good idea to use a striped Raid as a boot device. Even if anytning is backed up. As, with random access to small data blocks which is typical for a boot volume, it might even be slower than a single disk. But - for benchmarks or sequential transfers -, offering w/r speeds of 250-270MB/s, at least to my knowledge it is the fastest storage that can boot Mac OS in a Powermac.

A theoretical option would be a PCIe SATA II controller runing a SIL3132 chip, flashed with the Firmtek-Seritek Firmware, as this is the only chip with some fCode firmware available for and, by that, recognized by Open Firmware as "bootable".

But this would need
a) (possible) having a 1MB EEPROM or one soldered to it, to hold the complete firmware and
b) (as far as i know not possible. Even extensive Google didn't find such a card) at least a two-lane-interface to the PCIe
to be any faster.

So far my conclusion to the G5's maximal bootable storage upgrade options.
If anybody has anything better/faster in mind, would be happy to hear/read of.
 

flyproductions

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Jan 17, 2014
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There you go.

Give 'er four SATA SSDs, set up a RAID 0 and start rollin'. :D
Looks great!

But, as i found out by extended testing (more in a later post), booting from a RAID is completely pointless. But, if this really boots Leo and offers 3 Gbps per port even on PCIe 1.0 it would at least be a nice improvement over a single SSD attached to one of the onboard SATA I ports.
 
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flyproductions

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So after all, the fastest Mac OS-bootable "solution" for a G5 seems to be, what i have at the moment (temporary): A Raid 0 of two SSDs connected to the G5's onboard SATA I ports. Temporary, as i know it is in general not a good idea to use a striped Raid as a boot device.
So - after some more intense testing and benchmarking - i am back to one single boot-drive again!

This is because the testing 100% confirmd my suspicions: It is the far better option not only in regards of data loss. In practical use, it will even be the faster one! Sure, these RAID 0s offer nice speeds for sequential read/write transactions of big amounts of data. But this is not, what happens on a boot drive most of the time. There we have mostly random acces to small data blocks. And this is, where the RAIDs face their limits.

As the benchmarks show...

Xbench 1.3, disk test

RAID 0 of two identical 250GB Sandisk SSDs, attached to the G5's SATA I ports

Xbench Boot Raid.png

A single 500GB SAMSUNG 850 evo, attached to one of the SATA I ports

Xbench Single Boot Disk.png

In Xbench the RAID can not even shine in bigger sequential transfers. And anything with smaller blocks goes asolutely abysmal. So does the overall score, compared to the one of the single disk.

A better, most likely bit more realistic output shows intech's QuickBench.


Intech QuickBench 4.0

RAID 0, same as above

Quickbench, Boot Raid.jpg

Single disk
Quickbench, Single Boot Disk.jpg

At least it shows the half and one MB transfers benefitting of the RAID. But, as mentioned above, that's not the typical scenario on a boot disk. And with all the smaller stuff up to 16K the RAID just falls behind the single disk again.

So, added the advantages in regards of data security, it might well be the best booting solution for any G5 Powermac to just plug an SSD to one of the machines SATA ports...

...if the SAS controller presented in this thread doesn't show some consistantly higher transfer rates along with real boot capabilities. So i'm looking forward for this thing to arrive.
 
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Amethyst1

macrumors G3
Oct 28, 2015
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Sure, these RAID 0s offer nice speeds for sequential read/write transactions of big amounts of data. But this is not, what happens on a boot drive most of the time. There we have mostly random acces to small data blocks. And this is,
...also why SSDs completely destroy hard drives as boot and application drives.

...if the SAS controller presented in this thread doesn't show some consistantly higher transfer rates along with real boot capabilities. So i'm looking forward for this thing to arrive.
Can you test it with three or four SSDs in RAID 0 nonetheless to see what kind of speeds can be attained in the Quad when using four PCIe 1.0 lanes?
 
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flyproductions

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...also why SSDs completely destroy hard drives as boot and application drives.
That's why i have no rotating disks in mone of my machines anymore. Not even in the beige G3. At least not for OS X.
Can you test it with three or four SSDs in RAID 0 nonetheless to see what kind of speeds can be attained in the Quad when using four PCIe 1.0 lanes?
As far as i see, this thing is only two lane, just like the Accelsior. And in that case suggestion is, that more than two disks will be absolutely pointless, as the Accelsior shows, that even one single SATA III SSD nearly reaches the limit of the connector. It is 250MB/s per lane minus overhead. So it will not be able to transfer much more than 400MB/s, which the Accelsior almost hits with a single disk.

This is why this small one lane SATA III controller, i have installed for the optical drive doesn't pass 200MB/s, even with two drives in RAID 0 connected to it.
 
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reukiodo

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Nov 22, 2013
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The Tempo SSD doesn't seem to have boot support according to https://www.sonnettech.com/product/tempossd.html?tab=1 the documentation. Does anyone have this card with a G5 Quad and can validate?

For those with an older PCIX G5, using rabbitholecomputing's https://store.rabbitholecomputing.com/RETRO-SATA-PCI-p/rhc-sata-sii3112-pci-hard-card.htm SATA card should be bootable from a SATA-based M.2, thought it might be slower than the native SATA. I just want 2 large storage drives in the 3.5" slots so am looking for any other way to boot from a PCIe slot.
 

joevt

Contributor
Jun 21, 2012
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The Tempo SSD doesn't seem to have boot support according to https://www.sonnettech.com/product/tempossd.html?tab=1 the documentation. Does anyone have this card with a G5 Quad and can validate?

For those with an older PCIX G5, using rabbitholecomputing's https://store.rabbitholecomputing.com/RETRO-SATA-PCI-p/rhc-sata-sii3112-pci-hard-card.htm SATA card should be bootable from a SATA-based M.2, thought it might be slower than the native SATA. I just want 2 large storage drives in the 3.5" slots so am looking for any other way to boot from a PCIe slot.
It probably doesn't have an Open Firmware ROM and the G5 ROM doesn't have a compatible Open Firmware driver.

Does the controller have a SATA AHCI PCI device class (01:06:01)? I don't think Apple ever made an Open Firmware AHCI driver.

If you wanted to boot from it, you would have to setup a helper partition on a supported drive which then boots the OS X system that is connected to the Tempo SSD.
 

barracuda156

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Sep 3, 2021
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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!

I am also interested in this, since on of my SSDs in the Quad is AHCI on a PCIe card.

By the way, anyone done it with BSD?
 

flyproductions

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Jan 17, 2014
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I'm more interested in any PCIe card that the Quad can boot directly from.
You can try one of these cheap SAS-cards. If not allready present, they can be flashed with some OF Rom. All the info is in the thread.

They boot fine in G5s with double the speed of the onboard SATA. Even Raid 0s created with multiple SSDs connected to them are bootable. But i wouldn't recommend, as random r/w acces for small data chunks gets very slow.
 
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barracuda156

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Sep 3, 2021
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You can try one of these cheap SAS-cards. If notr allready present, they can be flashed with some OF Rom. All the info is in the thread.

They boot fine in G5s with double the speed of the onboard SATA. Even Raid 0s created with multiple SSDs connected to them are bootable. But i wouldn't recommend, as random r/w acces for small data chunks gets very slow.

Are those gonna work with SSDs which are not supported natively? (I have Intel 730 Series, I think.)
 

Amethyst1

macrumors G3
Oct 28, 2015
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Are those gonna work with SSDs which are not supported natively? (I have Intel 730 Series, I think.)
I tested a bunch of random Chinese "fantasy-name" SSDs and they all showed up and benchmarked fine on the LSI card (in a 2007 MBP using an ExpressCard-to-PCIe adapter to boot), so unless the 730 is very special/picky, I don't see why it wouldn't work.
 
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