June 14, 20179 yr So, I recently replaced my parity drive with a 10 TB drive and have decided that I'm saving up to buy another 10 TB drive to upgrade to dual parity when I get the chance. That made me think about what happens if the drives aren't exactly the same size. If I use two different brands of drives, and one is 10.1 TB and one is 10.2 TB, will unRAID still be able to use 10.1 TB of parity (and the extra .1 TB on the larger drive is just ignored)? Same question with a data drive, I guess. If I stay with single parity, and have a 10.1 TB parity drive, could I put a 10.2 TB data drive in my box and that last .1 TB is ignored? Or does the data drive absolutely have to be smaller than the parity drive?
June 14, 20179 yr 5 minutes ago, datruedave said: If I use two different brands of drives, and one is 10.1 TB and one is 10.2 TB, will unRAID still be able to use 10.1 TB of parity (and the extra .1 TB on the larger drive is just ignored)? Yes 5 minutes ago, datruedave said: If I stay with single parity, and have a 10.1 TB parity drive, could I put a 10.2 TB data drive in my box and that last .1 TB is ignored? Or does the data drive absolutely have to be smaller than the parity drive? No. Parity drive(s) must always be larger than data drives. There are some tricks around this (short stroking the data drive), but easier just to follow the rule, and swap around the drives in that case. But, AFAIK size differences even between manufacturers are rare, and usually only happen if you pull drives out of an external enclosure, or if you've managed to get an HPA partition on one of the drives. Edited June 14, 20179 yr by Squid
June 14, 20179 yr Community Expert 39 minutes ago, Squid said: But, AFAIK size differences even between manufacturers are rare, and usually only happen if you pull drives out of an external enclosure, or if you've managed to get an HPA partition on one of the drives. In fact, I would say that if you find yourself in the position of new drives of the same "advertised" capacity being slightly different in size, post back here so we can help you get to the bottom of this.
June 14, 20179 yr Author Ah, well, that's good to know, too. I have not actually encountered it with unRAID. I was just thinking back that several years (yikes, a decade?) ago a "1 GB drive" might have different actual capacities depending on the make and model. I figured that now that I'm looking at 10 TB drives, that the issue might be just as common.
June 15, 20179 yr Community Expert 2 hours ago, datruedave said: Ah, well, that's good to know, too. I have not actually encountered it with unRAID. I was just thinking back that several years (yikes, a decade?) ago a "1 GB drive" might have different actual capacities depending on the make and model. I figured that now that I'm looking at 10 TB drives, that the issue might be just as common. Different systems may report different sizes for the same disk depending on the "units" used for reporting. But if you look at the exact number of bytes these should be the same for any 6TB disk, for example.
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