ServerBuddies Support Blog

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

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).

Cpanellogd Overview.

WHM/cPanel processing related to the domain logs and bandwidth logs for Accounts, as well as service level logs for cPanel™ and Apache managed by the cpanellogd daemon. cpanellogd, in all versions of WHM/cPanel, is responsible for tracking log file size, rotation and parsing frequency. Any utility available to affect cpanellogd’s behavior is exposed in the web interface as a value field, checkbox, or note for custom configuration.

WHM/cPanel processing related to the domain logs and bandwidth logs for Accounts, as well as service level logs for cPanel™ and Apache managed by the cpanellogd daemon. cpanellogd, in all versions of WHM/cPanel, is responsible for tracking log file size, rotation and parsing frequency. Any utility available to affect cpanellogd’s behavior is exposed in the web interface as a value field, checkbox, or note for custom configuration.

iptables Overview

iptables features advanced logging, pre and post-routing actions, network address translation, and port forwarding all in one command line interface.

Using iptables

The first step in using iptables is to start the iptables service.
This can be done with the command:

The ip6tables services should be turned off to use the iptables.

To make iptables start by default whenever the system is booted, you must change runlevel status on the service using chkconfig.

The syntax of iptables is separated into tiers. The main tier is the chain. A chain specifies the state at which a packet is manipulated. The usage is as follows:

The -A option appends a rule at the end of an existing ruleset.

The chain is the name of the chain for a rule.
The three built-in chains of iptables (that is, the chains that affect every packet which traverses a network) are INPUT, OUTPUT, and FORWARD.

The -j target option specifies the location in the iptables ruleset where this particular rule should jump. Some built in targets are ACCEPT, DROP, and REJECT.