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Chapter 63. Storage

The kexec -e command might cause storage errors with advanced storage controllers

When using the kexec utility with the -e option, the system does not go through the standard Linux shutdown sequence before booting the next kernel. This might cause problems for systems employing advanced storage controllers, such as the Qlogic QMH2672 Fibre Channel adapter, because these controllers rely on the shutdown sequence to assure the storage has settled at the time of a reboot. When invoking the kexec -e command on such systems, storage related errors might occur as the kexec operation progresses, and the newly loaded kernel might fail to discover some or all attached storage.
If you see similar symptoms on your system when attempting kexec -e, use kexec without the -e option instead. This has been observed to work reliably. (BZ#1303244)

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 complete whenever autoactivation takes place. For information on the --activationmode complete option and automatic activation, see the vgchange(8) and pvscan(8) man pages.
Note that the event-driven autoactivation hooks are enabled when lvmetad is enabled with the global/use_lvmetad=1 setting in the /etc/lvm/lvm.conf configuration 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 initramfs (dracut) nor does this affect direct activation from the command line using vgchange and lvchange calls, which default to degraded activation mode. (BZ#1337220)