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RAID not readable after 10.12 - 10.13 upgrade

Hi all


We have a Mac Pro 5,1 (2010-2012) that is our primary workhorse and the four internal drive bays are configured as a RAID. Recently, due to pressure from clients who supply Adobe-related files for us to work with, we were forced to update our Adobe applications and this required an update from 10.12 (Sierra) to 10.13 (High Sierra). We did so, somewhat begrudgingly, only to be greeted after reboot by four dialogues boxes informing us that each of our RAID set were 'unreadable by with computer', or whatever it actually says. Whatever the precise message, we have a lot of information on that RAID that we'd really like to see right now and we are panicking just a little.


Has anyone else struck this situation and does anyone have a 'simple' solution?


TIA!

Mac Pro, macOS 10.12

Posted on Dec 14, 2019 8:45 PM

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11 replies

Dec 14, 2019 9:25 PM in response to Grant Bennet-Alder

Yes, the bays are configured as the main storage RAID in RAID5


Boot drive is an OWC Mercury Accelsior PCIe SSD in RAID0. There are two further SSDs, one in an optical bay and one on another PCIe card. Those two are the data drives.


The main RAID *IS* the backup system, hence the RAID5 configuration (ie: 1/4 the total drive capacity but sufficient redundancy). We can afford to lose two of the four drives and survive... what we didn't expect was to run an OS 'update' and lose everything!

Dec 16, 2019 1:33 PM in response to zande

I think you may have either had a multiple-drive failure, or simply did not notice when a drive dropped out and then another one as well.


I run a mirrored RAID on my server using MacOS 1-.13 High Sierra. Have not has any trouble, still perking right along.


as far as I have heard, there is nothing in that software update that precludes using RAID drives.


Are you using the Apple RAID card, or another approach?

Dec 16, 2019 5:20 PM in response to Grant Bennet-Alder

Four drives failed at once, coinciding with a system update? FWIW, there was monitoring running anyway so a single (or more) failure during normal operation would have been reported, as has happened in the past.


The issue arose immediately upon rebooting after the 10.12.x to 10.13.x upgrade. All was well before the upgrade to 10.13 but as soon as it rebooted, we got the four dialogues pop up with the 'this disk is unreadable - want to format?' message.


It's a software RAID.


I can't help but wonder if the newer file system has something to do with it? The question is how do I get around it?

Dec 16, 2019 9:36 PM in response to zande

Apple no longer supports upgrading macOS when using a software RAID boot drive. You need to install the macOS upgrade to a single drive, then clone it to the RAIDed drives. I think this started with High Sierra.


FYI, I've been told that Apple has removed booting macOS to a RAID with Catalina (not sure about Mojave).

Dec 16, 2019 10:49 PM in response to HWTech

Thanks for the response. This is not the case here though. The RAID is configured on the four drives in the four internal bays and is the backup/cold storage for the system. The data is on two SSDs, one in an optical bay and the other on a PCIe card. The boot drive is also on a PCIe card, the OWC Mercury Accelsior PCIe SSD in RAID0 which, happily enough, still boots under 10.13


We sat happily on 10.9.5 from 2014 to 2018 when Adobe forced us to 10.12 and now we have to upgrade to 10.13 to stay up to date with our clients. I'm a firm believer in "if it ain't broke, don't fix it" as these two old Mac Pros are our livelihood and downtime is costly.

Dec 23, 2019 8:49 AM in response to zande

You dodged the bullet. But Now I want to talk about BACKUP.


RAID is Not Backup. RAID merely extends the time to repair after a drive failure so that a disk failure does not always become a data disaster.


RAID does not protect you at all from human error, crazy software, and "just because" errors. You need a separate, disk based second copy of every file you want to see again tomorrow. And you need a rigorous way to be certain those backups get updated with changes files from time to time.


This needs to be a rigorous schedule based on factors that depend on your company. It needs to be frequent enough so that having to reconstruct the original files will never be so large an undertaking that it would be ruinous for to your company. (e.g., loss of all the memos you wrote this month might take only a few days to re-create. Loss of last week's Video edits would take a full week and more to re-create, and so the backup interval on those would need to be more frequent.


The other thing you need to protect your company against is natural disaster, such as earthquake or fire at your premises. This brings in the notion of A, B, C backups, where the oldest are brought in, about to be re-written, the newest are stored away from the computer, (at the other end of the building), and the last are stored off-site, at least on the other side of town.


Your files are likely so large that one drive cannot hold the entirety. That's OK, because built-in Apple RAID software supports "concatenated RAID" (which is not really RAID at all) but allows you to paste several large disks together and treat them as if they were one Volume. The only downside is that all the component drives must be mounted at once, so you will need some multi-drive enclosures.


If all your retirement money is tied up in the company, not doing this could leave you homeless instead of ready to go on vacation when you need to retire.


RAID not readable after 10.12 - 10.13 upgrade

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