Pegasus R6 and Catalina...

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  • Last Post 18 March 2020
Nicholas Kustreba posted this 14 March 2020

Well, this is not going very well at all.

I just got this thing and it doesn't really work.

It's still initializing the RAID volume but when I go to dump files onto it with Finder from a USB SSD, the transfer stops almost immediately.

I go into the Promise Utility and try to save the service report and even _that_ does not work!

Please tell me this is a joke...The Catalina developer beta came out last June!

The diagnostic report doesn't even save!?

Someone please help :(
I should've checked this before I got this but I assumed that since it was sold directly by Apple and Promise is such a well known company that there wouldn't be any major issues...sigh...

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Nicholas Kustreba posted this 18 March 2020

I figured out all the software issues but the speeds for parity raid are pretty awful
Working with support now to try to figure it out
RAID 0 speeds are great, over 700MB/s reads and 700 MB/s writes, stripe size doesn't matter.

RAID6 with 64K stripe size, reads are abominably bad, like 250 MB/s.  Same with RAID5.

Increasing the stripe size to 1M seems to resolve it partially, but the performance is not what I would call good...It's acceptable, but not good.


Parity RAID is always going to be slower than RAID0, but if there's more than a 20% drop in throughput with the same IO pattern, something's not right.

Right now with a 1M stripe size, 6 drive RAID6 group, writes are 550 MB/s and reads are 485 MB/s with Black Magic Disk Benchmark.

So by my math, that's a 36% drop in read performance from RAID0...yikes.
But as long as it's over 400 MB/s it'll work for what I need to do.

I would still like to get the performance up to where I think it should be, but we'll see how it goes.

Raghuraman Kannan posted this 18 March 2020

Hi Nicholas,

Pegasus units are fully compatible with MAC OS Catalina. If you have any issues with the unit, please register yourself as a user at https://support.promise.com/. Then save the report using the below steps and open a case. We will help you.

1) Open Promise Utility.

2) Click subsystem information icon on the top of the window.

3) Click the lock symbol on the left bottom corner of the screen to unlock the utility.

4) Click on save service report button to save the subsystem report and attach it to the case.

Thanks !

Nicholas Kustreba posted this 15 March 2020

Update again -- read speeds are abominably bad.

Writes are fine.

250 MB/s reads with Black Magic Benchmark...on a six drive RAID6 group.

So that's 40MB/s per drive...I would expect double that, or more, which is what writes are (~550MB/s-600MB/s) currently.


Already tested a single individual drive in passthru mode, gets over 100 MB/s reads and writes.

Something's wrong here :|

Read cache is enabled

I ran ctrl -a mod -i 1 -s "forcedreadahead=enable" in the CLI

Nicholas Kustreba posted this 14 March 2020

Update -- I isntalled the latest version of the Promise Utility and the problem is gone.

If you're in the same boat you can grab the tool from the Pegasus2 downloads page, it will still work with the Pegasus 1

Guess that was it.  The older version was causing the issue.  

 Also, ran into another problem -- the new version of the Utility kept saying there was a firmware update available -- however when I went to actually do it, it said it was successful, but then upon reboot / powercycle the firmware didn't actually get updated.

In order to fix that I had to manually download the 064 firmware release from the Pegasus2 download page and then manually flash it -- then the firmware actually did get updated.

I'm guessing the Pegasus2 is just the same thing as this with an updated thunderbolt chip?  IDK but the firmwares seem to be universal.

So this config seems to be stable, although it has *not* been stress tested yet:

MacMini8,1
Pegasus 1 R6 using StarTech TB3->TB1 adapter & Apple OEM TB1 cable
OS X 10.15.3
Promise Utility Version 4.04.0000.39 (C01)
Driver Version (PromiseSTEX) 6.2.13
Firmware 5.04.0000.64

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