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Chapter 60. Storage
LVM does not support event-based autoactivation of incomplete volume groups
If a volume group is not complete and physical volumes are missing, LVM does not support automatic LVM event-based activation of that volume group. This implies a setting of
--activationmode completewhenever autoactivation takes place. For information on the
--activationmode completeoption and automatic activation, see the
Note that the event-driven autoactivation hooks are enabled when
lvmetadis enabled with the
global/use_lvmetad=1setting in the
/etc/lvm/lvm.confconfiguration file. Also note that without autoactivation, there is a direct activation hook at the exact time during boot at which the volume groups are activated with only the physical volumes that are available at that time. Any physical volumes that appear later are not taken into account.
This issue does not affect early boot in
dracut) nor does this affect direct activation from the command line using
lvchangecalls, which default to
degradedactivation mode. (BZ#1337220)
vdo service is disabled after upgrading to Red Hat Enterprise Linux 7.6
Upgrading from Red Hat Enterprise Linux 7.5 to 7.6 disables the
vdoservice if it was previously enabled. This is because of missing
systemdmacros in the vdo RPM package.
The problem has been fixed in the 7.6 release, and upgrading from Red Hat Enterprise Linux 7.6 to a later release will no longer disable
Data corruption occurs on RAID 10 reshape on top of VDO.
RAID 10 reshape (with both LVM and
mdadm) on top of VDO corrupts data. Stacking RAID 10 (or other RAID types) on top of VDO does not take advantage of the deduplication and compression capabilities of VDO and is not recommended. (BZ#1528466, BZ#1530776)
System boot is sometimes delayed by ndctl
udevrule installed by the ndctl package sometimes delays the system boot process for several minutes on systems with Non-Volatile Dual In-line Memory Module (NVDIMM) devices. In such cases,
systemddisplays a message similar to the following:
INFO: task systemd-udevd:1554 blocked for more than 120 seconds. ... nvdimm_bus_check_dimm_count+0x31/0xa0 [libnvdimm] ...
To work around the issue, disable the
udevrule using the following command:
# rm /usr/lib/udev/rules.d/80-ndctl.rules
After disabling the
udevrule, the described problem no longer occurs. (BZ#1635441)
LVM might cause data corruption in the first 128kB of allocatable space of a physical volume
A bug in the I/O layer of LVM causes LVM to read and write back the first 128kB of data that immediately follows the LVM metadata on the disk. If another program or the file system is modifying these blocks when you use an LVM command, changes might be lost. As a consequence, this might lead to data corruption in rare cases.
To work around this problem, avoid using LVM commands that change volume group (VG) metadata, such as
lvextend, while logical volumes (LVs) in the VG are in use. (BZ#1643651)