This is the quote that we received. My question is on the amount of 532Tib.
Is this the amount before or after the Erasure Coding? If it is before, then the real usable amount would be 4/5 x 532TiB = TiB. Correct?
#What is the usable size for "4xSG6060_4TiB_4+1EC_ 532tib"?
weary rain
solid vine
are you increasing a grid or starting a new one? Just going to be hard to do 4+1 EC with only 4 nodes
weary rain
It's increasing. There are 4 existing nodes with 2+1 EC now. To make my question even more complicated, we are going to convert the existing 4 nodes to 4+1 from 2+1, how could you calculate the total of usable space including all 8 nodes? They all have the same model.
Currently for existing 4 nodes, on SG GUI dashboard, it shows total amount of 680TB used(it is almost full now). We can tier maximum of 370TB.
solid vine
well, usable space is a bit tricky anyway because you really don't want to go over 90% capacity... plus there is overhead in tiering itself... not all of the data in the 4MB chunks is valid data ... you can control this with the unreclaimed-space-threshold setting per aggregate
but a 4+1 EC configuration has generally a 20% overhead ... then other realities kick in
weary rain
For 4+1EC, the overhead should be 25% not 20%. So, the usable space should be 532/(1+25%) = 425.6T without considering the overhead in tiering. If we change EC for existing 4 nodes, then the usable space should be 425.6x2= 851.2T