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Diffstat (limited to 'mdadm.8.in')
| -rw-r--r-- | mdadm.8.in | 28 |
1 files changed, 28 insertions, 0 deletions
@@ -768,6 +768,34 @@ The file must be stored on a separate device, not on the RAID array being reshaped. .TP +.B \-\-data\-offset= +Arrays with 1.x metadata can leave a gap between the start of the +device and the start of array data. This gap can be used for various +metadata. The start of data is known as the +.IR data\-offset . +Normally an appropriate data offset is computed automatically. +However it can be useful to set it explicitly such as when re-creating +an array which was originally created using a different version of +.I mdadm +which computed a different offset. + +Setting the offset explicitly over-rides the default. The value given +is in Kilobytes unless an 'M' or 'G' suffix is given. + +Since Linux 3.4, +.B \-\-data\-offset +can also be used with +.B --grow +for some RAID levels (initially on RAID10). This allows the +data-offset to be changed as part of the reshape process. When the +data offset is changed, no backup file is required as the difference +in offsets is used to provide the same functionality. + +When the new offset is earlier than the old offset, the number of +devices in the array cannot shrink. When it is after the old offset, +the number of devices in the array cannot increase. + +.TP .BR \-\-continue This option is complementary to the .B \-\-freeze-reshape |