Logical Volume Backup

Logical Volume Backup

Metadata backups and archives are automatically created on every volume group and logical volume configuration change unless disabled in the lvm.conf file. By default, the metadata backup is stored in the /etc/lvm/backup file and the metadata archives are stored in the /etc/lvm/archive file.

How long the metadata archives stored in the /etc/lvm/archive file are kept and how many archive files are kept is determined by parameters you can set in the lvm.conf file. A daily system backup should include the contents of the /etc/lvm directory in the backup.

Note that a metadata backup does not back up the user and system data contained in the logical volumes. You can manually back up the metadata to the /etc/lvm/backup file with the vgcfgbackup command.

Finding files readable for everybody

find . -perm -444 -perm /222 ! -perm /111
find . -perm -a+r -perm /a+w ! -perm /a+x

These two commands both search for files that are readable for everybody (-perm -444 or -perm -a+r), have at least write bit set (-perm /222 or -perm /a+w) but are not executable for anybody (! -perm /111 and ! -perm /a+x respectively)

Logical Volume Creation Overview

The following is a summary of the steps to perform to create an LVM logical volume.

1. Initialize the partitions you will use for the LVM volume as physical volumes (this labels them).

2. Create a volume group.

3. Create a logical volume.

After creating the logical volume you can create and mount the file system.


LVM Architecture Overview

LVM Architecture Overview

LVM2 is backwards compatible with LVM1, with the exception of snapshot and cluster support. You can convert a volume group from LVM1 format to LVM2 format with the vgconvert command. For information on converting LVM metadata format, see the vgconvert(8) man page.

The underlying physical storage unit of an LVM logical volume is a block device such as a partition or whole disk. This device is initialized as an LVM physical volume (PV).

To create an LVM logical volume, the physical volumes are combined into a volume group (VG). This creates a pool of disk space out of which LVM logical volumes (LVs) can be allocated. This process is analogous to the way in which disks are divided into partitions. A logical volume is used by file systems and applications (such as databases).

The Sysstat Suite of Resource Monitoring Tools

Sysstat is a sophisticated tool.

Sysstat contains the following tools related to collecting I/O and CPU statistics:

iostat
Displays an overview of CPU utilization, along with I/O statistics for one or more disk drives.

mpstat
Displays more in-depth CPU statistics.
Sysstat also contains tools that collect system resource utilization data and create daily reports based on that data.

These tools are:

sadc
Known as the system activity data collector, sadc collects system resource utilization information and writes it to a file.

sar
Producing reports from the files created by sadc, sar reports can be generated interactively or written to a file for more intensive analysis.

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