thegizzard Posted February 4, 2018 Share Posted February 4, 2018 I am sure this is a simple question. I just added Parity 2 for the first time. It added about 4 TB of space to my array. With the new config I now have 2 8TB parity disks. Can someone explain why free space was added with my second Parity disk? Link to comment
trurl Posted February 4, 2018 Share Posted February 4, 2018 8 minutes ago, thegizzard said: I am sure this is a simple question. I just added Parity 2 for the first time. It added about 4 TB of space to my array. With the new config I now have 2 8TB parity disks. Can someone explain why free space was added with my second Parity disk? Not possible. You must be misinterpreting something. Link to comment
trurl Posted February 4, 2018 Share Posted February 4, 2018 This is the sort of question whose answer is obvious if you understand how parity works. Lots of things about unRAID make more sense if you understand parity. It's not complicated. Here is the wiki: https://lime-technology.com/wiki/UnRAID_6/Overview#Parity-Protected_Array Hopefully you haven't done something like accidentally formatting a data disk. That would certainly increase available space. You said "new config". You didn't actually New Config did you? Adding parity2 is just stop array, select disk for parity2, start array to sync parity2. Should take quite a few hours to sync 8TB. Link to comment
thegizzard Posted February 4, 2018 Author Share Posted February 4, 2018 Correct. I did not do a new config. All I did was add a new parity disk parity 2. I stop the array, and then I assigned the new disc to parity too. I thought I had a good understanding of how parity works when I have a single parity disk. I have not done any investigation on how parity to affects the size of the array. I assume that what is happening is exactly what should be happening. It does not look like an error. I am simply surprised that the size of the array increased by adding a parity disc. In the past, I do not remember increasing the size of the parity disk changing the amount of available free space in the array. I expect that what is happening is something that I simply do not understand but is all good. When I get back home I can show you a picture of the before and after configuration. Like I said it seems that half the size of the new disc was added to the amount of available free space in the array. It seems like the second parity disk allowed less of the data disks to be used for parity. Or something like that.Sent from my SM-N950U using Tapatalk Link to comment
JorgeB Posted February 4, 2018 Share Posted February 4, 2018 5 minutes ago, thegizzard said: I am simply surprised that the size of the array increased by adding a parity disc. That's impossible. Link to comment
SSD Posted February 4, 2018 Share Posted February 4, 2018 Adding 2nd parity will not result in more data space in the array. Do you have a before and after? Or even post a screenshot and highlight the number you are looking at to compare? Three possibilities if truly the array is reporting more space. Bug in the UI, misinterpretation of the number, or a mistake that deleted data. Link to comment
trurl Posted February 4, 2018 Share Posted February 4, 2018 Parity2 works basically the same as parity, just a little different calculation. Each parity bit corresponds to a bit on each of the data disks. Simply not possible for a change to the number or size of parity disks to increase available data space as we said. Size of parity disks are not included in total size of array. I have 2x6TB parity, 4x6TB +1x4TB data = 28TB total array size. 4x6 + 1x4 = 28 Link to comment
thegizzard Posted February 4, 2018 Author Share Posted February 4, 2018 This is the array now. It's building parity for parity disk 2 but shows 5.04 TB free in the array. Am I reading this correctly? Sent from my SM-N950U using Tapatalk Link to comment
thegizzard Posted February 4, 2018 Author Share Posted February 4, 2018 I have a before picture, but it is on my computer. Before I added parity 2, free space showed 1.46 or something TB free. I just made the change this am. Sent from my SM-N950U using Tapatalk Link to comment
trurl Posted February 4, 2018 Share Posted February 4, 2018 Your numbers add up correctly, as do mine. And as you can see, there is nothing for Size, Used, or Free for either parity disk, so they don't contribute anything. The only thing missing is some evidence that you had a different number previously. Link to comment
thegizzard Posted February 4, 2018 Author Share Posted February 4, 2018 Understood. I will be providing it shortly. Hopefully I am incorrect. Sent from my SM-N950U using Tapatalk Link to comment
thegizzard Posted February 4, 2018 Author Share Posted February 4, 2018 Ok. My apologies. It seems I have made so many changes recently that I lost track of how much space there was available in my array. It looks like I simply confused the amount of free space I had on the new disk 7, with the total space available in the array. See the history attached. Link to comment
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