my current snapraid array (4 data and 1 parity disks, 8TB each) is filling up, and so I'm planning to extend with larger disks (naturally), more precisely 5 18 TB disks. Now how do use the disks for Data and parity?
(Option "Cheap") 5x8TB + 4x18TB data + 18TB Parity, which is discouraged by the snapraid developers because of the imbalance between data and parity drives;
(Option "Wasteful") 5x8TB + 3x18TB data + 2x18TB Parity, which means that I could only use 60% of the new disk space, and only gives a minimal increase in protection from drive failure.
(Option "Split") Use two arrays, i.e. leave the current array as is, and create a new one in the same fashion (4+1). This is currently my favourite.
(Option "Complicated") Use one array with 4 of the old and 4 of the new disks, the old parity disks only protecting 8TB of the entire pool and and a new parity disk protecting everything. Is this even possible? Is ist difficult to set up?
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Whenever you change the size of your disks, you need to start replacing the partity drive(s) with larger ones first, then match the data drives thereafter. That has been my strategy in the past.
So basically either option 1 or 2. Where do you see that an imbalance in drive sizes is discouraged? I don't think it is, for as long as your parity drives are at least as large as your largest data drive.
Last edit: cannondale0815 2023-07-27
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Hi,
my current snapraid array (4 data and 1 parity disks, 8TB each) is filling up, and so I'm planning to extend with larger disks (naturally), more precisely 5 18 TB disks. Now how do use the disks for Data and parity?
(Option "Cheap") 5x8TB + 4x18TB data + 18TB Parity, which is discouraged by the snapraid developers because of the imbalance between data and parity drives;
(Option "Wasteful") 5x8TB + 3x18TB data + 2x18TB Parity, which means that I could only use 60% of the new disk space, and only gives a minimal increase in protection from drive failure.
(Option "Split") Use two arrays, i.e. leave the current array as is, and create a new one in the same fashion (4+1). This is currently my favourite.
(Option "Complicated") Use one array with 4 of the old and 4 of the new disks, the old parity disks only protecting 8TB of the entire pool and and a new parity disk protecting everything. Is this even possible? Is ist difficult to set up?
Whenever you change the size of your disks, you need to start replacing the partity drive(s) with larger ones first, then match the data drives thereafter. That has been my strategy in the past.
So basically either option 1 or 2. Where do you see that an imbalance in drive sizes is discouraged? I don't think it is, for as long as your parity drives are at least as large as your largest data drive.
Last edit: cannondale0815 2023-07-27
I don't think 4 is possible.
I would do 2, which I would call "simple".
You'll be upgrading the 8TB someday and the larger parity will be ready for you.
Thanks for the replies. By "imbalance" I meant that a single parity drive is only recommended for up to 4 data drives, not for nine.