raid 0 problem on mac pro 5,1

[parisinvest]

hi you all, i recently tried to use 2x sm951 512go via pci-express to built a raid 0 on my macpro 5,1, but can't make it through; i've tried two ways, raid 0, then restore from time machine, the restore was complet, but can't restart normally, it goes to have process with logo, then restart, again and again; second way, raid 0, then reinstall high sierra from usb, can't get passe the installation, system error "cant built restart section" then it stop there, never finish the process; i've tried change the slot, but wont help. could anyone can tell how to solve the problem please? thank you so much.

 

[Draeconis]

I seem to recall someone posting you can't install and boot APFS on an AppleRAID array.

 

[bsbeamer]

I repurposed two SATA Samsung SSDs in a RAID-0 and they needed to be freshly reformatted (believe was in 10.13.2) before they would be acknowledged by Disk Utility properly for a RAID setup. Formatted HFS+.

APFS was NOT compatible at that time for RAID setups and do not believe it is. APFS was giving me a lot of issues with the system drive when it was "upgraded" to APFS during 10.13 install.

My personal suggestion would be to install to a fresh SATA drive and then try using Carbon Copy Cloner to clone/transfer to the setup RAID. Unsure if that is possible long-term, but would get around the install issue.

 

[parisinvest]

hi many thanks for you all reply, i've tried to install el capitan on this raid 0 setup, it worked, so the problem was the apfs, but when i get entered desktop, the disk speed has no difference with one M.2 sm951, before raid i had 1420/1450m/s, after raid it does 1380/1480, why is that, i've read article that the raid AHCI could do 6000m/s, dont understand where is the problem.

 

[JedNZ]

What PCIe slot is it in? Are both blades on the same PCIe adapter?

I understand that PCIe slot 2 only gets half the expected bandwidth (PCIe 2.0 = 500MB per lane, so if the PCIe card is 4 lane then the most you'll get is a theoretical maximum of 2000MB, which in real world speeds is the 1500MB you see). That's why I have my Accelsior S PCIe (SATA III) card in slot 2 with a SATA III SSD drive - it can only R/W ~500MB anyway - and it's why I have my NVMe in a PCIe adapter in slot 3 - the blade is capable of 3000/1800, but I will only ever get ~1450/1500 due to the maximum throughout of PCI 2.0.

Have you tried the other slots?

 

[h9826790]

hi many thanks for you all reply, i've tried to install el capitan on this raid 0 setup, it worked, so the problem was the apfs, but when i get entered desktop, the disk speed has no difference with one M.2 sm951, before raid i had 1420/1450m/s, after raid it does 1380/1480, why is that, i've read article that the raid AHCI could do 6000m/s, dont understand where is the problem.

To achieve greater than 1500MB/s. You need to

1) Install no more than one SM951 in slot 3 + 4. In other words, at least one SM951 in slot 2 in your case.

2) use pciutils to set the slot 2 SM951 to negotiate at PCIe 2.0 speed.

Or

Buy the expensive Amfeltec / Highpoint adaptor (which has a PCIe switch onboard), and install one or more SM951 on that adaptor, and install that adaptor in slot 2.

 

[parisinvest]

To achieve greater than 1500MB/s. You need to

1) Install no more than one SM951 in slot 3 + 4. In other words, at least one SM951 in slot 2 in your case.

2) use pciutils to set the slot 2 SM951 to negotiate at PCIe 2.0 speed.

Or

Buy the expensive Amfeltec / Highpoint adaptor (which has a PCIe switch onboard), and install one or more SM951 on that adaptor, and install that adaptor in slot 2.

thank you so much, i'll try later when i have time and keep you guys informed

 

[eksu]

I seem to recall someone posting you can't install and boot APFS on an AppleRAID array.

I'm running on Apple Pro Raid on APFS with 4 SATA HDD's in Raid10, planning on moving to some SAS drives soon.

Also, I was able to run with APFS since High Sierra came out no problem

 

[Draeconis]

I'm running on Apple Pro Raid on APFS with 4 SATA HDD's in Raid10, planning on moving to some SAS drives soon.

Also, I was able to run with APFS since High Sierra came out no problem

I’m intrigued why you’d move to SAS drives in 2018, when an SSD array would easily max the capacity of the RAID card?

You also say you’re using APFS, but not specifically booting from it? Didn’t realise you could format a spinning disk as APFS, does Disk Utility let you do that or do you have to use diskutil?

 

[eksu]

I’ve been booting off of my RAID array and running APFS since the firmware patch for APFS booting dropped.

I’n trying to max out my capacity with >=2.2tb drives. I can get 3tb seagate constellation es.2 drives for 58$ each. My current array with the original WD drives is suprisingly fast, and the newer SAS drives would be even better.

Eventually I’ll boot off of a PCIE NVME solution.

 

[Draeconis]

I’ve been booting off of my RAID array and running APFS since the firmware patch for APFS booting dropped.

I’n trying to max out my capacity with >=2.2tb drives. I can get 3tb seagate constellation es.2 drives for 58$ each. My current array with the original WD drives is suprisingly fast, and the newer SAS drives would be even better.

Eventually I’ll boot off of a PCIE NVME solution.

Nice, certainly an interesting solution. I never got on with my RAID card, but it was an Apple RAID with a dodgy battery, so that’s probbaly why