Partioning Raid 1+0 volume

You do not partition SoftRAID volumes.

What you could do is resize the volume to 4TB, then create a new volume to mirror your disks with (or back up to it with SuperDuper)

the downside of doing it that way is the 1TB will be the "last" volume on the disks, hence slower. this may not be ideal for a boot volume, but if it is holding data from your boot volume (its a clone copy), then that may be acceptable performance wise.

You do not partition SoftRAID volumes.

What you could do is resize the volume to 4TB, then create a new volume to mirror your disks with (or back up to it with SuperDuper)

the downside of doing it that way is the 1TB will be the "last" volume on the disks, hence slower. this may not be ideal for a boot volume, but if it is holding data from your boot volume (its a clone copy), then that may be acceptable performance wise.

Thanks for this. I did it the opposite way, shrinking the volume to 1 Tb and making a new 5 Tb volume called "Santorini" with the rest of the space. They seem to work, but whenever I boot into El Capitan (but not when I boot into Snow Leopard), either on the 1 Tb volume I call "Thera" or on another disk I call "Mull", I get a quick sequence of dialogue boxes, three each for Thera and Santorini. The first tells me the volume is missing some disks, the second that the disks are out of sync, and the third that the disks are now in sync. Should this concern me? Is there something I should do to prevent this happening? Did it matter that I reversed the order of the two volumes from what you suggested?

FYI, the two primary disks are internal to the Mac Pro, the secondaries in a "Probox" connected by USB3, both volumes the same.

Martin

I have to guess that the USB disks are not showing up quickly enough. SoftRAID has a time out under Mirror Preferences. Change it to 1 minute. That may resolve this. (If this is a RAID 4/5/10, then change this under the RAID preference tab)

You do not partition SoftRAID volumes.

I am researching this issue of partioning SoftRaid volumes, and am confused because I have come up with conflicting information. See quotes and link below, thanks!

[..]

Quote :

About Using Software RAID
RAID-5 / RAID-4 Can be Partitioned to Suit
Last updated June 08, 2014

A RAID-5 or RAID-4* setup is not restricted to one huge volume; it’s perfectly fine to create more than one volume to suit one’s needs. SoftRAID makes it trivial to create such partitions regardless of the type of RAID (or non-RAID).

As shown below, four 5TB drives in an OWC Thunderbay enclosure have been used to create three 5TB volumes instead of one 15TB single volume: Master, Archive1, Archive2. It could just as well have been 4TB each. This approach can serve important goals ... (Continued)

-- Mac Performance Guide, June 8, 2014
http://macperformanceguide.com/SoftwareRAID-RAID5-partitioning.html

This does not conflict. A SoftRAID volume is whatever RAID type and size you want. Determine the size at time of creation.

You do not take an existing SoftRAID volume and "split" or "partition" it into multiple volumes.

If you want two volumes, create two volumes. They can be different RAID types.

Just don't think in terms of splitting volumes into segments or partitions. It does not work like that.

This does not conflict. A SoftRAID volume is whatever RAID type and size you want. Determine the size at time of creation.

You do not take an existing SoftRAID volume and "split" or "partition" it into multiple volumes.

If you want two volumes, create two volumes. They can be different RAID types.

Just don't think in terms of splitting volumes into segments or partitions. It does not work like that.

OK cool, that's good news. But how do you create two volumes from the outset?

For instance, I want to create two RAID5 volumes from three hard drives ... When I select the 3 drives, and then right click to get the command "New Volume" I see that you can select the volume size, but not the number of volumes ?

In my case, I have three 6TB drives for a RAID5. I tried creating a smaller than Max size, 8TB volume (in this case 12TB in max size) thinking I could create another volume with the 4TB left over. I DID get the 8TB volume, but I am not seeing the 4TB left over.

Thanks for your help, much appreciated.

Just create the first volume as you did, without using the max capacity. Just specify the size of this volume.

Then create a new volume. Select the disks. Specify the size needed.

Then create a third new volume. etc.

Its very straightforward.

So are these different size soft raid volumes just like an Apple-disk-utility-partioned disk, in that they can each be a start up drive?

I would like to have 2 different start up volumes for 2 different computers, and different Mac OS version software.
Is that possible with the Non-raid disk setting for 2 volumes.

You can create as many volumes and as many RAID level volumes as you want.

To make a SoftRAID volume bootable, however the "boot cache" must be set. This must be set by running SoftRAID with the same flavor OS as the target volumes (10.9.x for 10.9.x, etc)

Once set, it should stay set. You can have multiple boot volumes, no problem. Each Volume has its own boot cache.

I would like to have 2 different start up volumes for 2 different computers, and different Mac OS version software.

Hi Bob,

Just want to add that while having two versions of Mac OS (on the same computer) sounds like a great idea, I was never able to get it to work in any practical sort of way.

The problem I encountered is in setting the boot disk from system preferences.
If you are running the more recent version of your two OS, you can go to system prefs and choose the older version to boot from. However once back in the older version, it will not see the newer version to boot from. It's a one way ticket. You can go back to a previous version, but cant go forward to a more recent version.

If you have figured out a way around this, I'd sure like to know ;)

-Julian

It is not only possible, but we use this in testing. For example a 2011 Mac Mini with a 10.6.8, 10.7.5, 10.8.5, 19.9.5 and another with 10.8.x, 10.9.5, 10.10.5 and 10.11.3, all bootable volumes on them, with the disks in SoftRAID format. Its important for testing to have such machines.

The one important fact is you will need a second copy of each OS flavor, typically on a Thumbdrive, to set the boot cache, usually a one time event. Any SoftRAID volume needs to have the boot cache "rebuilt", unless it was created from an OS X installer. Setting the boot cache is a one time event, generally.

When you clone the OS to a SoftRAID volume, then you need to boot from the same flavor OS, run SoftRAID and "rebuild boot cache". Then you can boot from that volume, irregardless if you also boot from higher or lower OS X installs on different volumes on the same disks.

OS X does not preclude booting from older/newer OS startup volumes. I normally use the option key to start from, but you can also Set Startup.

I just performed this with a Mac Mini, with two OS X installs: 10.10.x and 10.8.x.
I booted up from 10.8. then used "Set Startup to 10.10". then the same in reverse.

Hope this helps explain this subject.