Installation guide

Appendix D. LVM Volume Group Metadata
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• A version number which is incremented whenever the metadata gets updated
• Any properties: Read/Write? Resizeable?
• Any administrative limit on the number of physical volumes and logical volumes it may contain
• The extent size (in units of sectors which are defined as 512 bytes)
• An unordered list of physical volumes making up the volume group, each with:
• Its UUID, used to determine the block device containing it
• Any properties, such as whether the physical volume is allocatable
• The offset to the start of the first extent within the physical volume (in sectors)
• The number of extents
• An unordered list of logical volumes. each consisting of
• An ordered list of logical volume segments. For each segment the metadata includes a mapping
applied to an ordered list of physical volume segments or logical volume segments
D.3. Sample Metadata
The following shows an example of LVM volume group metadata for a volume group called myvg.
# Generated by LVM2: Tue Jan 30 16:28:15 2007
contents = "Text Format Volume Group"
version = 1
description = "Created *before* executing 'lvextend -L+5G /dev/myvg/mylv /dev/sdc'"
creation_host = "tng3-1" # Linux tng3-1 2.6.18-8.el5 #1 SMP Fri Jan 26 14:15:21 EST
2007 i686
creation_time = 1170196095 # Tue Jan 30 16:28:15 2007
myvg {
id = "0zd3UT-wbYT-lDHq-lMPs-EjoE-0o18-wL28X4"
seqno = 3
status = ["RESIZEABLE", "READ", "WRITE"]
extent_size = 8192 # 4 Megabytes
max_lv = 0
max_pv = 0
physical_volumes {
pv0 {
id = "ZBW5qW-dXF2-0bGw-ZCad-2RlV-phwu-1c1RFt"
device = "/dev/sda" # Hint only
status = ["ALLOCATABLE"]
dev_size = 35964301 # 17.1491 Gigabytes
pe_start = 384
pe_count = 4390 # 17.1484 Gigabytes
}
pv1 {
id = "ZHEZJW-MR64-D3QM-Rv7V-Hxsa-zU24-wztY19"
device = "/dev/sdb" # Hint only