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23.5. Logical Volume Manager
LVM provides userspace tools that are used to manage the kernel's DM devices. LVM will shift the start of the data area (that a given DM device will use) to account for a non-zero
alignment_offset
associated with any device managed by LVM. This means logical volumes will be properly aligned (alignment_offset=0
).
By default, LVM will adjust for any
alignment_offset
, but this behavior can be disabled by setting data_alignment_offset_detection
to 0
in /etc/lvm/lvm.conf
. Disabling this is not recommended.
LVM will also detect the I/O hints for a device. The start of a device's data area will be a multiple of the
minimum_io_size
or optimal_io_size
exposed in sysfs. LVM will use the minimum_io_size
if optimal_io_size
is undefined (i.e. 0
).
By default, LVM will automatically determine these I/O hints, but this behavior can be disabled by setting
data_alignment_detection
to 0
in /etc/lvm/lvm.conf
. Disabling this is not recommended.
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