M8Wd4ZJGbP Posted October 16, 2008 Share Posted October 16, 2008 This isn't clearly spelled out anywhere that I could find. Say I have 7x500gb drives. Would a 501gb drive be enough for parity if it existed? Quote Link to comment
SSD Posted October 16, 2008 Share Posted October 16, 2008 It has to be as big (or bigger) than the largest data disk. With all 500G data drives, a 500G parity is perfect. Quote Link to comment
M8Wd4ZJGbP Posted October 16, 2008 Author Share Posted October 16, 2008 Ok, thanks.. Quote Link to comment
SSD Posted October 16, 2008 Share Posted October 16, 2008 I was surprised you'd have trouble locating this very basic piece of information about unRAID, but when I looked I did not immediately find it either. Here is a description of how parity works in unRAID. It will help you understand why the drive doesn't have to be any larger than the largest drive. There have been a few reports of certain motherboards / disk controllers "hiding" a very small amount of space on a disk drive. This can result in, for example, 2 500G drives being of slightly different sizes. Although this is pretty rare, it has caused some users consternation as unRAID will not accept a parity drive smaller than the largest data drive, even if the size difference is tiny (even 1 sector would be too much). Quote Link to comment
M8Wd4ZJGbP Posted October 16, 2008 Author Share Posted October 16, 2008 I have problems like that with raid controllers in the past.. They should all round the drive sizes down a little to some acceptable figure.. Quote Link to comment
WeeboTech Posted October 16, 2008 Share Posted October 16, 2008 I have problems like that with raid controllers in the past.. They should all round the drive sizes down a little to some acceptable figure.. The Areca's have a configurable option to do this. Quote Link to comment
RobJ Posted October 17, 2008 Share Posted October 17, 2008 Added to the FAQ (with a link back), here. Feel free to edit or expand. Quote Link to comment
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