Can a SoftRAID volu...
 
Notifications
Clear all

Can a SoftRAID volume be part of a Fusion Drive?

 rnb2
(@rnb2)
Active Member Customer

I know that Fusion Drives can't be converted to SoftRAID volumes, but is it possible to use a SoftRAID volume as part of a Fusion Drive? I know it's probably not advisable without a good backup system (since the Fusion Drive is effectively RAID0), but is it possible?

Quote
Topic starter Posted : 24/07/2017 12:46 am
(@softraid-support)
Member Admin

No, we do not support this, only one driver can control a disk.

thanks for asking about this, the SSD/HD capability is a feature we would like to add.

ReplyQuote
Posted : 24/07/2017 1:17 pm
 rnb2
(@rnb2)
Active Member Customer

Thanks, makes sense.

I'm just a photographer trying to optimize the drives attached to my new 2017 iMac. I have 3x480GB SSDs and 3x2TB 2.5" HDs, with two of each in a Thunderbay mini set up as RAID 0+1 - the SSDs are my startup disk + current jobs, backed up to the internal 1TB Fusion Drive nightly (more for convenience than any actual need, given the external drive setup). The remaining SSD and HD are in a Mediasonic 2-bay USB-C enclosure that can do hardware RAID 0/1/JBOD/separate drives, so I've set up a home-made Fusion Drive there (photo archive), and the remaining 3TB of space in the Thunderbay is set up as a RAID0 backup of the Mediasonic enclosure. I have a complete offline backup of everything, as well, so I'm protected against the fragility of the Fusion Drive/RAID0 portions of the setup.

From a performance standpoint, I could switch to a 2xSSD RAID0 in the Mediasonic enclosure, with the remaining SSD and 3 HDs in the Thunderbay mini, but I can't see an elegant way to set that up so that I don't have to choose what to put on the SSD or HDs, which I'd like to avoid. Fusion Drive lets me do that, but then I don't have a way to combine multiple HDs into one Volume.

Probably best to just stick with what I have and stop worrying about it, but it's in my nature to Always Be Optimizing...

ReplyQuote
Topic starter Posted : 24/07/2017 2:21 pm
(@softraid-support)
Member Admin

Here is another alternative for you:

Take the 3 40GB SSD drives. Create a RAID 4 volume. Use that for all your data/images. that is about 1TB volume.

Back it up to the internal Fusion Drive, using Carbon Copy Cloner or SuperDuper. You can set up a nightly schedule with both applications.

I don't know how much total capacity you need, but consider the 3 2TB drives as a 3 disk mirror, where you keep one of the disks off line and rotate it with another secondary. this gives you a 2TB instantly available off site disk. swap out the secondary disk weekly/monthly depending on your needs.

Your setup would be:

TB Mini: 3 SSD's and 1HDD (primary to mirror)
USB C enclosure with 1 disk at all times, then roate the second disk on a schedule.
Fusion drive is a clone of the Primary data in the RAID 4 volume.

If the USB C enclosure does not support hot swapping, then consider leaving it in JBOD mode and being on line mirrors to the 2TB in the Mini.

this maximizes your redundancy and gives great performance with the SSD drives.

ReplyQuote
Posted : 24/07/2017 2:58 pm
 rnb2
(@rnb2)
Active Member Customer

Thanks for taking the time to respond!

That's an interesting option, but I think I'd lose too much performance on my photo archive with no SSD, and would I gain that much going from RAID 0+1 on my boot drive to RAID 4 (faster writes)? With my current setup, I have two "live" copies of everything, plus one offline, and at least one SSD included in each volume holding my primary copies of my data. My photo archive doesn't get as much use as my current work, but the Fusion Drive should keep anything that I'm accessing on even a semi-regular basis on a fast drive.

Thanks again for the idea, though - it does give me something to think about.

ReplyQuote
Topic starter Posted : 24/07/2017 6:35 pm
 rnb2
(@rnb2)
Active Member Customer

Thanks for taking the time to respond!

That's an interesting option, but I think I'd lose too much performance on my photo archive with no SSD, and would I gain that much going from RAID 0+1 on my boot drive to RAID 4 (faster writes)? With my current setup, I have two "live" copies of everything, plus one offline, and at least one SSD included in each volume holding my primary copies of my data. My photo archive doesn't get as much use as my current work, but the Fusion Drive should keep anything that I'm accessing on even a semi-regular basis on a fast drive.

Thanks again for the idea, though - it does give me something to think about.

Resurrecting this for another hypothetical:

2xSSD in the USB-C enclosure (boot drive, backed up to Fusion every night)
1xSSD + 3xHDD in the TBay4 mini

Configure the TBay4 as follows:

SSD + first 480GB of each HDD as RAID4 - would SoftRAID know to put parity on the SSD to speed up writes?
Next ~20-100GB of each HDD as RAID0 for scratch
Remaining space on HDDs as RAID5 archive space

Also, Is there a practical limit to how many volumes should be on a single HDD? In this case, there could be cases where the Scratch volume and RAID volumes “quarrel” a bit - how much of an issue is that likely to be?

Thanks again for the advice/pointers!

ReplyQuote
Topic starter Posted : 13/08/2017 1:20 pm
(@softraid-support)
Member Admin

On the RAID 4, you can manually assign the SSD to be parity.

Each volume will work independently, but if you access two at the same time, you can expect some performance drops because the disks are accessing two locations at once.

ReplyQuote
Posted : 14/08/2017 1:09 pm
 rnb2
(@rnb2)
Active Member Customer

On the RAID 4, you can manually assign the SSD to be parity.

Each volume will work independently, but if you access two at the same time, you can expect some performance drops because the disks are accessing two locations at once.

Perfect - thanks!

ReplyQuote
Topic starter Posted : 14/08/2017 4:16 pm
Share:
close
open