17.07.2016 05:09, Sébastien Luttringer пишет: > Hello, > > «btrfs fi usage» report size differently between single,RAID0,RAID1,RAID5,RAID6 > and RAID10. > > The test is done with 2 files of 1.4GiB each on 4x10GiB devices. I used balance > to get size between profiles. > > Data,single: Size:4.00GiB, Used:2.85GiB > /dev/sdb 1.00GiB > /dev/sdc 1.00GiB > /dev/sdd 1.00GiB > /dev/sde 1.00GiB > > Data,RAID0: Size:8.00GiB, Used:2.85GiB > /dev/sdb 2.00GiB > /dev/sdc 2.00GiB > /dev/sdd 2.00GiB > /dev/sde 2.00GiB > > Data,RAID1: Size:4.00GiB, Used:2.85GiB > /dev/sdb 2.00GiB > /dev/sdc 2.00GiB > /dev/sdd 2.00GiB > /dev/sde 2.00GiB > > Data,RAID5: Size:6.00GiB, Used:2.85GiB > /dev/sdb 2.00GiB > /dev/sdc 2.00GiB > /dev/sdd 2.00GiB > /dev/sde 2.00GiB > > Data,RAID6: Size:6.00GiB, Used:2.85GiB > /dev/sdb 3.00GiB > /dev/sdc 3.00GiB > /dev/sdd 3.00GiB > /dev/sde 3.00GiB > > Data,RAID10: Size:4.00GiB, Used:2.85GiB > /dev/sdb 1.00GiB > /dev/sdc 1.00GiB > /dev/sdd 1.00GiB > /dev/sde 1.00GiB > > For single,RAID0,RAID10 profiles, the sum of device sizes is equal to > total size. Like total size is the "byte allocated size" for all > devices. > > For RAID1,RAID5,RAID6 profiles, sum of devices sizes is more than the > total size. Looks like the redundancy was subtracted from the total. > Like total size is the "profile size allocated". > > So, why RAID1 and RAID10 are reporting their sizes differently? This > confuse me. > In your example only RAID10 is different. RAID1 shows 4GiB on 8GiB total disks which matches "redundancy subtracted". But yes, I also wonder why RAID10 does not respect it.
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