Any difference between an array that has grown and one freshly initialised?

This is one for the people who really understand BeyondRAID. Is there a noticeable difference (in capacity, or any other measurable parameter) between a freshly initialised Drobo disk pack consisting of equal capacity drives on the one hand and, on the other, one that has “grown” over time from a smaller capacity to the same capacity through gradual replacement of drives?

My 5N started out with three 1 TB drives that I happened to have spare (1+1+1+0+0). I added a 5 TB drive to each of the two empty slots (1+1+1+5+5). Then I replaced each of the smaller drives with a 5 TB drive, waiting for data relaying to complete in each case (1+1+5+5+5) -> (1+5+5+5+5) at which point I enabled dual drive redundancy (1+5+5+5+5 DDR) -> (5+5+5+5+5 DDR). I’m wondering if my data layout is less than optimal and has more triple mirrors in place of double parity stripes than it would have if I had freshly initialised the 5 x 5 TB array. Triple mirrors are less efficient in terms of capacity than double parity stripes but maybe BeyondRAID optimises them away.

hi maybe in the meantime, you might find some helpful info by looking at the patent?

it certainly would be interesting to setup a matrix table, to note down the various space sizes that are available, as well as confirmed pros and cons for each method of upgrade.

Hi Paul. I have spent some time reading the patent but it’s so tediously convoluted that it’s quite difficult to follow. There are a couple of training videos on YouTube - about eight people in a classroom and one of Drobo’s engineers in front of a whiteboard - that are quite illuminating, but there isn’t the depth of information to be found. If I had the time I’d do some experimenting myself - after all, I have nothing on my Drobo I don’t have elsewhere. Perhaps it was too much to hope for a reply from someone at Drobo when there are people with real problems that need sorting.