I figured I'd share my experience with migrating from hardware raid (2 Areca RAID 6 arrays, each consisting of 24 drives), to a dual tRAID setup.
I was running Areca controllers (ARC-1170 and ARC-1680) for many years and they were generally speaking trouble free. The 1170 had 24 SATA ports on it, each being connected to a mating port on a passive backplane in a SuperMicro 846 chassis. The 1680 was connected to a LSISASX36 expander backplane in a 2nd 846 chassis.
That setup served me well over several years although I did have several close calls with 2 drives failing in a short time frame and even had a 3rd fail during a rebuilt twice, which dropped the entire array. By sheer luck, I was able to get one of the 3 failed drives back online again for just long enough to restore the array. The array on the 1170 controller started out with all 1TB drives and the 1680 array with 2TB drives. Over the years as drives failed (I have gone through about 20 failed drives or more), I typically replaced with same size, but sometime went larger if a sale was going on. Of course with hardware RAID, the extra capacity is lost since the smallest drive dictate usable space.
After another episode of almost loosing an entire array again, I decided to make the switch to FlexRAID, or more specifically, the tRAID variant. It was a painful and learning experience to migrate the existing data (about 45TB) onto the new arrays. I had previously tested tRAID on the Areca 1680 controller with some spare drives using pass-through mode, and it worked ok, although write speed left something to be desired at around 30 MBps.
So the first order of business was to copy all the data off the 24TB array on the 1170 PCIX controller. The great thing about FlexRAID is that you can copy data to individual drives and then make them part of an array without loosing any data. So I picked up enough 4TB drives to copy all the data from the 24TB array. Once that was done, I blew away the old 24TB array and setup a new tRAID array after turning the 1170 controller into JBOD mode. Turns out that did not work out well for a variety of reasons I won't go into here. So I decided to make some hardware changes.
I upgraded both of my SuperMicro backplanes to LSISAS2X36 ones and picked up a pair of IBM 1015 HBA controllers seen below. These are just re-badged LSI SAS2008 based controllers.
The first thing I did was to flash them both to the latest SAS9211-8i IT firmware with no boot BIOS.
I was now able to stand up tRAID1 with no issues. It took about 21 hours to calculate the parity for the 2 PPUs. (tRAID2 shown below, but tRAID1 was exactly the same).
Next I copied all the data that I could from the 2nd Areca RAID6 array onto tRAID1. This was a slow process since the data was only copying at around 30 Mbps still. I was in no rush and it was all unattended and completed in about 5 days. What didn't fit on tRAID1 was copied onto other devices on my network.
With that done, I decommissioned the 1680 controller and installed the SAS2 backplane in the external chassis. I also ran a 2nd SFF-8087 cable to each of the backplanes to utilize the 2nd 4 lane port on each controller. Wow what a difference! I was now able to copy at 60Mbps into either tRAID array!
Here's a shot showing all 8 channel LEDs lit up on both controller as I'm copying data from one to the other:
Here's a Disk Management view showing the 48 tRAID virtual drives. So between the virtual and physical drives, I now have just under 100 drives in this server. Disk Manager takes a little while to load now.
Here's a view from the server desktop showing the 2 pool drives for each tRAID array:
And a view from the FlexRaid manager showing the physical drives and tRAID1 status:
Next I picked up a 64GB SSD drive to use as a "Landing Disk". This is a new feature in tRAID where any new data added to the array goes here first, so no more 30 or 60Mbps write speed limitation. I went ahead and added a 3rd IBM 1015 controller to the server and migrated my boot drive (Samsung 840 120GB and the 64GB landing disk) to it. This one was also flashed to the "IT" firmware, but I included the BIOS this time since I had to be able to go in and configure it to boot off the Samsung.
Couple of shots of the 3 controllers:
And finally a show of the BIOS screen. This was before I removed 2 of the controllers from the boot order.
The landing disk feature has completely eliminated the one annoyance I had with converting to software raid, namely the write performance. Of course if I need to copy more than 64GB at a time, I'll exhaust the "buffer" but now that I'm done with my massive data migration, I don't see this ever being an issue.
I can finally sleep good at night again!