default or selected kernelversion does not have config value CONFIG_MD_RAID5_RESHAPE.
Result is shown for kernelversion 5.3.7
Support adding drives to a raid-5 array
configname: CONFIG_MD_RAID5_RESHAPE
Linux Kernel Configuration
└─>Device Drivers
└─>Multiple devices driver support (RAID and LVM)
└─>Support adding drives to a raid-5 array
In linux kernel since version 2.6.20 (release Date: 2007-02-04)
A RAID-5 set can be expanded by adding extra drives. This
requires "restriping" the array which means (almost) every
block must be written to a different place.
This option allows such restriping to be done while the array
is online.
You will need mdadm version 2.4.1 or later to use this
feature safely. During the early stage of reshape there is
a critical section where live data is being over-written. A
crash during this time needs extra care for recovery. The
newer mdadm takes a copy of the data in the critical section
and will restore it, if necessary, after a crash.
The mdadm usage is e.g.
mdadm --grow /dev/md1 --raid-disks=6
to grow '/dev/md1' to having 6 disks.
Note: The array can only be expanded, not contracted.
There should be enough spares already present to make the new
array workable.
If unsure, say Y.
requires "restriping" the array which means (almost) every
block must be written to a different place.
This option allows such restriping to be done while the array
is online.
You will need mdadm version 2.4.1 or later to use this
feature safely. During the early stage of reshape there is
a critical section where live data is being over-written. A
crash during this time needs extra care for recovery. The
newer mdadm takes a copy of the data in the critical section
and will restore it, if necessary, after a crash.
The mdadm usage is e.g.
mdadm --grow /dev/md1 --raid-disks=6
to grow '/dev/md1' to having 6 disks.
Note: The array can only be expanded, not contracted.
There should be enough spares already present to make the new
array workable.
If unsure, say Y.