Would the Promise Pegasus R6 12TB be a good investment?

[Erik Lindahl]

We have two Promise Pegasus R4’s in our shop – one serving as our disk for the fileserver, one serving as our media drive for an editing station. No issues what so ever.

The R6 of 2-series will basically give you better speed and more storage as well as TB2 pass-through. I’d recommend looking into how the drives are formatted as that can have huge impact on read / write speeds.

If you only use TB1 devices today (i.e an iMac) the Pegasus is cheaper than the Pegasus2.

[Brett Sherman]

Is the R8 too much of a price increase. If you’re planning on RAID5 the more bays you have the less storage you waste. With R6 – you throw away 1/6th of the capacity on parity. With R8 it’s 1/8th.

So an R6 with 12 TB yields 10 TB for $2300 – $230/TB

An R8 with 24TB yields 21TB for $3500 – $167/TB

So if you need room to grow, I’d bite the bullet an get the R8. Of course I burn through about 10 TB a year.

[Jeremy Garchow]

What Brett says.

It is relatively cheap to double your capacity.

Yes, it’s a good investment. I would also get the TB2 version, not the TB1 version.

[Dave Jenkins]

I have been using the R6 since January with the new mac pro and it’s been perfect! I’m very happy with it. Speeds are 800 MB’s read & write.

Dajen Productions, Santa Barbara, CA
Mac Pro 3.5MHz 6-Core Late 2013
FCP X

[Rick Lang]

I believe I saw that R8 performance was even faster than R6 if that is a concern. Also enable pre-fetching to improve video READ performance. Copied from the Promise Knowledge Base 10394:

How to bench mark Pegasus2 R8
There are several bench tools out there among them are Black Magic Disk Speed Test and AJA System Tests.

These tools are ok to gauge basic throughput. Before you begin your benchmark testing we recommend to enable the aggressive pre-fetching AKA “controller forced read ahead” on your Pegasus2.

Promise plans to enable controller forced read ahead by default in the upcoming service release.

NOTE: Controller forced read ahead is most beneficial if you are working with Audio and Video files where the IO access is large block sequential IO.
Small block random IO will not benefit from this setting.

How to enable controller forced read using Promise CLI:

1. Login using your Administrator and from a terminal in your Mac host type “promiseutil”

2. From our CLI type: ctrl -a mod -i 1 -s “forcedreadahead=enable”

3. Confirm the setting is now enabled issuing the following command: ctrl -v

Rick Lang

iMac 27” 2.8GHz i7 16GB

[Mitch Ives]

[Mark Dobson] ” I’ve also read that whilst this is a Thunderbolt 2 I won’t actually see any speed increase for the type of work I do, 2K single file based editing.”

You don’t mention what machine you’re using? If it’s a machine that only has TB1 ports, then no you won’t see the full speed. Even if you have a single TB2 port like a Retina MBP, once you plug in a TB1 device in the chain, such as a monitor, additional HD, etc. everything gets pulled down to TB1 speeds.

With the new Mac Pros, you have 6 TB2 ports, but only three controllers, so you need to be careful how you plug things in. Plug all TB2 devices into two of the ports on a dedicated controller. Then plug the TB1 devices into a different set of ports assigned to a separate controller… leaving the last set that are tied to the HDMI port alone as long as possible.

Google “MacPro TB2 port layout” to see which ones to use IF you are on a new MacPro…

Mitch Ives
Insight Productions Corp.

“Criticism may not be agreeable, but it is necessary. It fulfills the same function as pain in the human body. It calls attention to an unhealthy state of things.” – Winston Churchill

[Mark Dobson]

[Mitch Ives] “You don’t mention what machine you’re using? If it’s a machine that only has TB1 ports, then no you won’t see the full speed. Even if you have a single TB2 port like a Retina MBP, once you plug in a TB1 device in the chain, such as a monitor, additional HD, etc. everything gets pulled down to TB1 speeds.”

Yes, I should have said, It’s a late 2012 3.4 i7 iMac. But no doubt I’ll be getting a New MacPro at some stage later this year so I would go for the T2 model.

[Rick Lang] “I believe I saw that R8 performance was even faster than R6 if that is a concern. Also enable pre-fetching to improve video READ performance. Copied from the Promise Knowledge Base 10394:”

I don’t think I would ever use the 32TB capacity of the R8 although the 18TB R6 could be a bit more future proof.

[Brett Sherman] “So an R6 with 12 TB yields 10 TB for $2300 – $230/TB

An R8 with 24TB yields 21TB for $3500 – $167/TB”

That’s an interesting calculation and would seem like a no brainer if money were no object.