Redundancy question

OK im posting here since this since it applies to 3 DRI products

I have a pro with 8 drives and DDR on.

i have 7 x 2tb and 1 x 1.5tb

drobo only had about 1.3 tb of free space

im replacing the 1.5 with a final 2tb one.

i pulled the 1.5tb drive. it said it cant protect my data (expected behaviour - but was we know, since i had DDR, it is still protection against the failure of another single disk)

now. this is where my question comes in. as it is, my pro shows as having 0 free space (as expected) the drive i removed was larger than the amount of free space it had before, so it cant rebuild onto the remaining disks (as expected).

It IS still protected against another disk failure, since i had DDR and pulled ONE.

now. if i open dashboard and change to SDR… it shows as having over 1TB of free space again (as expected) and has begun to rebuild onto the remaining 7 disks.

my question. during this rebuild (FROM a degrade DDR pack - back to a healthy SDR pack), is my data at risk from a drive failure.

If i had just left it as a degraded DDR pack until my new drive arrived, it would NOT have been at risk from a second drive failure.

i did not wnat to leave it like that, since it shows zero available space, and i need to copy some more stuff onto it while i am waiting for the final 2tb drive to arrive.

by telling it to convert to SDR it make the space instantly available. however - does this mean its just jettisonned all the DDR data which meant it was still protected against a second drive failure? is it now just a degraded SDR pack and its vulnerable until the rebuild finishes? or is it a degraded DDR pack rebuilding back to healthy SDR pack , and still protected the whole time.

i HOPE i explained that clearly.