Experience with OWC Mercury Pro U.2 Dual Storage Solution?

[GrumpyCoder]

Anyone got experience with the OWC Mercury Pro U.2 Dual? Now that we finally have MBPs that can be mobile workstations and full desktop replacements, I’d like to update my storage/backup solutions. I’ve always had additional drives in my Mac Pros and (slower) external solutions for long time storage and backup.

I would like to avoid going the PCIe-route as for long term usage it’s dead with Apple.

The Mercury Pro U.2 Dual seems interesting as a dedicated NVMe box. OWC claims up to 2800MB/s, but I’d assume that’s Raid0 or Raid10 with their SoftRAID solution. But over how many NVMes? What can I realistically expect from a) a single NVMe, b) two in Raid0, c) three in Raid0 and d) four in Raid0 or Raid10? I’d like to add one fast volume for processing data and I’d use the slots in one bay for that if I have to.

The second bay I’d like to use as a backup for the internal 2TB, preferably fast. The rest will be for backup purposes of the fast processing volume. In addition I’m backing up to large (10 to 16TB) spinners and a NAS (usually once per week), while the fast backup is daily.

Any thoughts? Any alternatives?

Thanks in advance.

 

[joevt]

I would like to avoid going the PCIe-route as for long term usage it’s dead with Apple.

Not sure what this means. NVMe and U.2 and Thunderbolt use PCIe. The OWC Mercury Pro U.2 Dual doesn't appear to use SATA.

The Mercury Pro U.2 Dual seems interesting as a dedicated NVMe box. OWC claims up to 2800MB/s, but I’d assume that’s Raid0 or Raid10 with their SoftRAID solution. But over how many NVMes? What can I realistically expect from a) a single NVMe, b) two in Raid0, c) three in Raid0 and d) four in Raid0 or Raid10? I’d like to add one fast volume for processing data and I’d use the slots in one bay for that if I have to.

The second bay I’d like to use as a backup for the internal 2TB, preferably fast. The rest will be for backup purposes of the fast processing volume. In addition I’m backing up to large (10 to 16TB) spinners and a NAS (usually once per week), while the fast backup is daily.

I don't see any information describing the PCIe fanout.

Obviously there is one Thunderbolt -> PCIe 3.0 x4 switch1 -> two PCIe ? x? U.2 -> PCIe ? x? switch2 -> four PCIe ? x? NVMe (considering the OWC U2 Shuttle for 4 NVMe per U.2)

But there's a lot of question marks.

Worst case:
Thunderbolt -> PCIe 3.0 x4 switch1 of the Thunderbolt controller -> two PCIe 3.0 x2 U.2 -> PCIe 3.0 x2 switch2 -> four PCIe 3.0 x1 NVMe.
This only allows 750 MB/s per NVMe. 1500 MB/s per U.2. 2800 MB/s total.
This would be similar to the OWC Express 4M2 except the OWC Mercury can connect 8 NVMe.

Medium case:
Thunderbolt -> PCIe 3.0 x4 switch1 of the Thunderbolt controller -> two PCIe 3.0 x2 U.2 -> PCIe 3.0 x2 switch2 -> four PCIe 3.0 x2 NVMe.
1500 MB/s per NVMe. 1500 MB/s per U.2. 2800 MB/s total.

Best case:
Thunderbolt -> PCIe 3.0 x4 switch1 of the Thunderbolt controller -> PCIe 3.0 x4 switchX -> two PCIe 3.0 x4 U.2 -> PCIe 3.0 x4 switch2 -> four PCIe 3.0 x4 NVMe.
2800 MB/s per NVMe, U.2, and total.

I found this:
https://www.owcdigital.com/products/u2-shuttle#tech-specs
https://eshop.macsales.com/item/OWC/U2SHUTTLE/
https://www.anandtech.com/show/16424/ces-2021-owc-introduces-35-u2-ssd-carrier
which says the four NVMe in each U2 have PCIe 3.0 x2 each. The ASM ASM2812X has 12 lanes total = 4 for upstream, 8 for downstream in this configuration.

So now we just need to know if the OWC Mercury Pro U.2 Dual contains switchX or not. This https://eshop.macsales.com/item/OWC/TB3MPDU000S/ says not. So this is the result:
Thunderbolt -> PCIe 3.0 x4 switch1 of the Thunderbolt controller -> two PCIe 3.0 x2 U.2 -> PCIe 3.0 x4 switch2 -> four PCIe 3.0 x2 NVMe.
1500 MB/s per NVMe. 1500 MB/s per U.2. 2800 MB/s total.
This is the medium case - the x4 upstream of the U.2/switch2 is bottlenecked by the x2 downstream of Thunderbolt/switch1.

 

[joevt]

Of course, you should look for reviews for actual numbers. The 1500 MB/s I suggested is more like 1630MB/s according to this:
https://www.techradar.com/reviews/owc-mercury-pro-u2-dual-external-drive
which would make my 750 MB/s estimate for x1 more like 815 MB/s.

 

[GrumpyCoder]

Not sure what this means. NVMe and U.2 and Thunderbolt use PCIe. The OWC Mercury Pro U.2 Dual doesn't appear to use SATA.

Sorry, should have been more clear. I meant PCIe card based solutions with external PCIe enclosure. I’ve had my share of trouble with enclosures, some are good, some are bad and I’d really like a proven all-in-one-box solution this time around.

Of course, you should look for reviews for actual numbers. The 1500 MB/s I suggested is more like 1630MB/s according to this:
https://www.techradar.com/reviews/owc-mercury-pro-u2-dual-external-drive
which would make my 750 MB/s estimate for x1 more like 815 MB/s.

Thank you, that doesn’t sound too bad. I’ll have to dig a little deeper into it. I found a few other solutions in the meantime, but will have to read into it as well and maybe make a comparison spreadsheet in the next week or so. Will have to find out what other soft RAID solutions are out there besides OWC’s solution. I’ve mostly used hardware RAIDs in the past.

 

[joevt]

Sorry, should have been more clear. I meant PCIe card based solutions with external PCIe enclosure. I’ve had my share of trouble with enclosures, some are good, some are bad and I’d really like a proven all-in-one-box solution this time around.

Well, the only difference between a PCIe enclosure and a U.2 or NVMe enclosure is the connector shape and the size of the enclosure and the amount of power. I have a GPU connected to an NVMe enclosure using an NVMe to PCIe adapter for example.

Thank you, that doesn’t sound too bad. I’ll have to dig a little deeper into it. I found a few other solutions in the meantime, but will have to read into it as well and maybe make a comparison spreadsheet in the next week or so. Will have to find out what other soft RAID solutions are out there besides OWC’s solution. I’ve mostly used hardware RAIDs in the past.

If you used a Sonnet Echo III Desktop then you could put three OWC Accelsior 8M2 PCIe cards inside for triple the number of SSDs. Plus all SSDs would be capable of 2800 MB/s without RAID since the PCIe switches of the Echo III Desktop and the Accelsior 8M2 have no x2 bottleneck. Those PCIe switches are expensive compared to the Thunderbolt switch (basically free with the Thunderbolt controller) and the ASMedia switch because they have many more lanes. The Echo III Desktop has some x8 slots, so you would need a riser for any x16 PCIe card. https://forums.macrumors.com/threads/thunderbolt-3-m-2-nvme-ssd-enclosures.2027925/post-30814810

RAID doesn't make much sense for Thunderbolt when there's no x2 bottleneck unless you want redundancy or to combine the SSDs into a single volume or if you use 3000 MB/s SSDs that have poor performance in Thunderbolt (800 MB/s).

 

[GrumpyCoder]

Well, the only difference between a PCIe enclosure and a U.2 or NVMe enclosure is the connector shape and the size of the enclosure and the amount of power. I have a GPU connected to an NVMe enclosure using an NVMe to PCIe adapter for example.

I ran into some compatibility trouble in the past with some cards and enclosures. I would assume buying the full package form one company would mean full compatibility, but I could be wrong. I'm really looking for something lug & play.

If you used a Sonnet Echo III Desktop then you could put three OWC Accelsior 8M2 PCIe cards inside for triple the number of SSDs. Plus all SSDs would be capable of 2800 MB/s without RAID since the PCIe switches of the Echo III Desktop and the Accelsior 8M2 have no x2 bottleneck.

RAID doesn't make much sense for Thunderbolt when there's no x2 bottleneck unless you want redundancy or to combine the SSDs into a single volume or if you use 3000 MB/s SSDs that have poor performance in Thunderbolt (800 MB/s).

I thought about Sonnet Echo indeed, either Desktop or Express. Besides the speed limit as you say, which requires RAID to solve, it's a little cheaper. 4x 1TB is cheaper than 1x 4TB for a single volume + the cost of the enclosure + cards. I'll have to do the math on this. I can't see myself needing more than 8 NVMe slots when running with RAID and without getting exact quotes from my usual supplier, I think it's still cheaper than a single Sonnet + Accelsior. The clear advantage would be, I won't need RAID with such a solution. I couldn't do any more research on this yet, but hopefully next week. Thanks again. I will certainly update this once I made a decision on this.

 

[johnmcboston]

"follow".

Looking at the same drive. Something faster than an HD to keep all my Mac files off of my system in use (will make moving to a new computer easier in the future). The raid 0 option seems to get good enough speed for my needs - playing music off of it, editing photos, and such.

 

[satcomer]

I your looking only for speed then look at the thread Thunderbolt 3 m2-NVME SSD Enclosures! just read the whole thread get the whole speed testing!

 

[johnmcboston]

I your looking only for speed then look at the thread Thunderbolt 3 m2-NVME SSD Enclosures! just read the whole thread get the whole speed testing!

not sure I'll read all 27 pages, but a good thread, thanks