PROMISE Pegasus (RIP) = ARC-8050

[bergert]

I bought two PROMISE PEGASUS R1-6 (Thunderbolt1, silver): one in 2011 and the second unit in 2013.

2011 R1-6: 6x Ultrastar 4TB disks, RAID-6
2013 R1-6: 6xSeagate NAS 4TB, RAID-6

Both units worked flawless, for many years...

I did measure IO speed, and it was 650MB/sec originally. In 2019 IO speed dropped to around 270MB/sec - I cannot tell if this is due to disk wear, or some other issue.

In 2017, the first unit (2012, after 5 years of use!) started to have disk failures (disk disappeared, no bad blocks). At first, I replaced the disk with a spare. Soon, the same slot failed again - and I used my second spare disk. Then another slot failed. At that point, I tested the disk using a SATA adapter (DiskWarrior). After 3 days of read and write - DiskWarrior came back and told me the disk is OK. I bought a R2-6 (Thunderbolt2, black), wiped the configuration (at the time PROMISE did not sell diskless units). Installed the disks. It looked kind of strange, the black enclosure and the silver trays (I did not bother to replace the trays). Moreover, the new enclosure is still working today: I put back the originally failed disk, and rebuilt the RAID-6 in the R2 enclosure.

It is quite sad, that PROMISE does not sell spare parts like the backplane. Therefore, I had to buy a full enclosure (more below).

In 2019, the second enclosure (2013, after 6 years of use) had a disk off-line. This time I immediately tested the disk using my trusty SATA adapter and DiskWarrior Demo (my DW license had since expired). After 5 hours without errors, I stopped the testing.

Because of the unwillingness’ of PROMISE company to sell spare parts, and the obviously bad quality of the backplane (I have 3 units in use, two failed after 5 and 6 years of use).
Do not get me wrong: Going back to 2012, I would still buy the PROMISE, simply because at the time there did not exist any better product.

I have now replaced both PROMISE R6 enclosures, with an ARECA 8050T3-8 (Thunderbolt3, 8 slot). I’m still using my 2011 macMini (Thunderbolt1): the ARECA is connected using a TB1-TB1 cable and the Apple USB-C-TB2 adapter dongle (the dongle is plugged into the ARECA). I am now using 6x10TB Seagate NAS disks in RAID-6, rebuild took 52 hours (more than 2 days). It took 5 days to copy the data from both R-6’s units …

Rest in peace PEGASUS R6!

Notes: I paid less for the 8050T3-8 (without disks), than what I paid for the PROMISE R2-6 populated with 2TB disks, for which I have no use. PROMISE now does sell a diskless R2-6, but does not sell a diskless R3-6 (Thunderbolt 3 is only sold with disks). And the R3-6 costs $800 more than the 8 slot ARECA!

Notes: I never had a disk failure, not on the Enterprise (Ultrastar), not on the NAS disks. I am using the (2012) array for about 4.5hours x 365days x 7years = 11500 hours (visible in the SMART status of the disks). The disks each show more than 2300 power on events (6.3 years, powered on every single day).

I decided for the 8-slot for a number of reasons:
- If I need more space I can just addd a disk (up to two)
- I can add a spare disk (PROMISE can do this, but you need to have an empty slot)
- In case a disk fails, I can plug in a spare disk into another slot

Now, I have a single 40TB volume mounted:
https://forums.macrumors.com/threads/promise-pegasus-r6-18tb-errors.1274291/#post-15556717 (my previous report, 2012)

 

[bergert]

The ARC-8050T3-8 has been running since 2019, powered up/down almost every day (~300 days/yr). This week I extended the 6-disk RAID-6 by adding a 7th disk (7x10TB = 50TB volume). Migration took 79hours; volume expand 4 hrs. The Ironwolf warrany ran out in 2021. Before doing the epxand, a full backup to disk.

I purchased another 8050T3-8 (~2020, don't remember exactly); using the 4TB spare disks purchased for the PROMISE (never used, sitting in the drawer). March/23 one disk failed, Tested with SATA-USB adapter: capacity shrunk by 50% (4TB -> 2TB). 4 disk RAID-6 (4x4TB = 8TB volume, for personal data). replaced with spare, rebuild ok. This is my first dead disk, on ARECA since 2019. Was using the 8050 with MacPro(2014) TB2-USBC dongle. Now with MacStudio.

Two TL-4000 tape library now retired. For 40TB: 30x LTO-5 cartriges cost $900, 3x Exos 16TB cost $780. Library with one LTO-5 drive costs $10k.

Now, I have 3 generations of full backups (3x10TB, 3x10TB, 3x16TB) in my drawer. Backup is always off-line, preferable off-site. For the next 2 years, I'll do incremental to disk (every month or so).

The facts speak for themselves.

 

[srgz]

Same problem here…bay 1 keeps having errors where the drive goes offline and the promise app says the drive was pulled and then re-inserted even though it wasn’t. Replaced the drive with a different drive, rebuild, and what a coincidence…same fkn issue. I connect the drives to a USB3->SATA6 bridge and run diagnostics and test them individually outside of the RAID, and they’re fine. Because ofc they are.

Promise are a horrible disgusting company.

They won’t even sell power supplies. Nothing. Go buy a new one, that’s what their support says. And people wonder why no one uses hardware RAID anymore. This is why. They’re basically scammers. They’ve got warehouses full of these components, and won’t even sell the parts at all, not even at a premium.

I also have a gripe with these Pegasus backplanes not supporting SAS drives, despite the RAID chip that they’re using being able to. Why not, you ask? Because a SAS capable backplane would cost ~50 cents more per. bay to produce. On a storage array that costs thousands of dollars where they’re already making an insane amount of profit margin.

Even crazier, they designed the Pegasus products to have modular backplanes that can be easily swapped — the 4 bay, 6 bay, and 8 bay units all use the same main board, and then the backplane is modular and uses a PCIe style connector. It allows them the flexibility in manufacturing to do it this way. Modularity when it’s convenient for them, but not for the customer…don’t you dare ask to buy a spare backplane, the answer is GFY!

I’m having to go the route of buying a non working one of these for parts and then swapping the backplane, I guess.

Might as well replace the cheap noisy ass fans they use on these junk boxes too, while I’ve got it open…because yeah let’s use a the cheapest most ********* and noisiest fan manufacturer we can find on a premium storage array once sold and recommended by Apple.

Sooner or later I suspect the same thing is going to happen on the new backplane, as this kind of issue is indicative of a systemic manufacturing problem. BTW, if they used SAS capable backplanes, chances are they wouldn’t be having this problem, as the traces would be up to SAS signaling standards and way overkill for SATA drives. SAS signaling runs at higher voltages and allows for longer traces and cable runs, and is also backwards compatible with SATA via STP (serial ata tunneling protocol).

The only benefit of the Promise Pegasus 1 and 2 arrays is that they use a very common RAID chip (PMC PM8001) and as a result, have drivers available for just about every OS, including VMware ESXi.
You should even be able to get it working on Linux and FreeBSD, although don’t expect hot plug or wake / sleep functionality (which no one really uses on a storage server anyway).

They also make a driverkit system extension (not KEXT) for modern versions of MacOS that still works on new Macs and should continue working, baring some unforeseen TB compatibility problems with some future version of TB / USB.