build kernel for arm64

slcklnx · 02-18-2021, 06:10 PM

hello dear Linux experts. I rebuild the kernel for the arm64 operating system Armbian and see that there are hardcoded raid0 raid1 included in the kernel

Code:

[-*-] raid0

Code:

[-*-] raid1

why is tough so important? why not modular? what role does raid play for arm?

why can't the raid be turned off?

Brains · 02-19-2021, 09:54 PM

Quote:

Multiple devices driver support (RAID and LVM) ----[*] Multiple devices driver support (RAID and LVM) --->
--- Multiple devices driver support (RAID and LVM)
< > RAID support (NEW)
< > Block device as cache (NEW)
< > Device mapper support (NEW)

The above is for current Linux 5.11 kernel. Multiple devices driver support needs to be enabled before RAID can be enabled. You likely have something else enabled in the kernel that enabled RAID by default. With current Linux kernel in make menuconfig you toggle the highlight to "Help" and you'll get more information. Below is the help information for RAID highlighted in blue above. It shows what other kernel features will "select/enable" RAID highlighted in blue.

Quote:

CONFIG_BLK_DEV_MD:
This driver lets you combine several hard disk partitions into one
logical block device. This can be used to simply append one
partition to another one or to combine several redundant hard disks
into a RAID1/4/5 device so as to provide protection against hard
disk failures. This is called "Software RAID" since the combining of
the partitions is done by the kernel. "Hardware RAID" means that the
combining is done by a dedicated controller; if you have such a
controller, you do not need to say Y here.
More information about Software RAID on Linux is contained in the
Software RAID mini-HOWTO, available from
<https://www.tldp.org/docs.html#howto>. There you will also learn
where to get the supporting user space utilities raidtools.
If unsure, say N.

Symbol: BLK_DEV_MD [=n]
Type : tristate
Defined at drivers/md/Kconfig:16
Prompt: RAID support
Depends on: MD [=y]
Location:
-> Device Drivers
-> Multiple devices driver support (RAID and LVM) (MD [=y])
Selected by [n]:
- DM_RAID [=n] && MD [=y] && BLK_DEV_DM [=n]