neohidra

Indeed - it is because by default Unraid formats disk with Reflink enabled. I see no point in using this feature since it will consume around 0.7% of the available disk space. You can find example of how to manually format disk, but I do something like this. In case the drive is already part of the array you have to: stop the Array (Main > Array Operations > Stop) change the disk File system type to something else (Main > Array Devices > Disk # > File system type:) start the Array (Main > Array Operations > Start) now format the drive manually stop the Array change back the File system type of the disk to XFS start the Array Unraid 6.11 by default is producing XFS drives with the following properties: Apr 8 00:37:06 Tower emhttpd: shcmd (270): xfs_growfs /mnt/disk2 Apr 8 00:37:06 Tower root: meta-data=/dev/md2 isize=512 agcount=6, agsize=268435455 blks Apr 8 00:37:06 Tower root: = sectsz=4096 attr=2, projid32bit=1 Apr 8 00:37:06 Tower root: = crc=1 finobt=1, sparse=1, rmapbt=0 Apr 8 00:37:06 Tower root: = reflink=1 bigtime=1 inobtcount=1 Apr 8 00:37:06 Tower root: data = bsize=4096 blocks=1465130633, imaxpct=5 Apr 8 00:37:06 Tower root: = sunit=0 swidth=0 blks Apr 8 00:37:06 Tower root: naming =version 2 bsize=4096 ascii-ci=0, ftype=1 Apr 8 00:37:06 Tower root: log =internal log bsize=4096 blocks=521728, version=2 Apr 8 00:37:06 Tower root: = sectsz=4096 sunit=1 blks, lazy-count=1 Apr 8 00:37:06 Tower root: realtime =none extsz=4096 blocks=0, rtextents=0 In order to disable reflink option you have to reformat the disk - which means that the data stored on this device will be lost. With the command bellow you can format (data will be erased from the device) disk /dev/md2: mkfs.xfs -m crc=1,finobt=1,reflink=0 -l su=4096 -s size=4096 -f /dev/md2 This way on 6TB you should get about 40GB additional space compared to the default formatting in Unraid.