The issue with the commands used is that the mirroring operation will take some time; the mirroring of 1TB of (possibly) empty data will need to be established before the volume is made available to the administrator. An alternative command sequence could be:
# lvcreate l 1 n datavol /dev/vg01 # lvextend m 1 /dev/vg01/datavol # lvextend L 1048576 /dev/vg01/datavol
This command sequence will establish a one-extent volume that is subsequently mirrored. The mirroring operation will take a minimum amount of time; mirroring one extent does not take a significant amount of time. The subsequent lvextend command to extend the size of the volume will allocate extents to both sides of the mirror simultaneously . This process is instantaneous. The overall command sequence is significantly shorter to execute than the original command sequence.
A2:
The data in any swap area is transient information that is lost after a reboot. As such, there is no point in having MWC consistency for swap areas; in fact, MWC consistency is bad for overall system performance when applied to swap areas, because it involves additional IO, which will affect overall system IO performance. To effect the change to a Primary swap area, the system will need to be booted into LVM -maintenance mode because the lvchange command can be applied only to an unopened logical volume.
A3:
The (brief) troubleshooting methodology looks at first glance to be quite sound. The major problem is that when the first 1MB of disk is corrupted the entire LIF volume will be lost. This means it will be impossible to boot the system to the ISL level. The LIF directory and LIF volume will have to be recovered first. This will require the use of Core Install/Recovery Media.
A4:
It is not possible to provide high availability and improve IO performance with LV PV Links. LVM PV Links offer only a high availability solution.
A5:
A mapfile is simply a text file detailing a number beside a logical volume name . The number details the logical volume minor number within the volume group . This number is used to identify extents belonging to the logical volume stored in a bitmap in the VGDA. If the numbers used in the mapfile correspond to minor numbers stored in the VGRA , the vgimport command will succeed. The names associated with the minor numbers are important for applications and files such as /etc/fstab to function properly. If all this information is correctly entered in a manually created mapfile , a vgimport command will be completely successful. If the mapfile cannot be constructed , a vgimport can be accomplished without the “m <mapfile> . The resulting logical volumes will be given default names, e.g., lvol1 , lvol2 , and so on. After further investigation, the device files associated with each logical volume can be renamed using the mv command to reflect the correct names of each logical volume.
