VPS Hosting Stuff

Introduction:

In general csf is giving good compatibility with cpanel servers . But in a vps (openvz or Virtuzzo) the csf configuration is something different.

Sometimes you may get an error as follow after the csf installation in vps

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Error: iptables command [/sbin/iptables -v -A LOGDROPIN -p tcp -m limit --limit 30/m --limit-burst 5 -j LOG --log-prefix 'Firewall: *TCP_IN Blocked* '] failed, at line 196

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So how to resolve this issue. Let us do it as follows,

There are two steps to configure the csf in vps

i)Main vps server ( The host server ,in which the vps nodes are running) configuration

ii) Vps node configuration.

Main vps serverconfiguration

Before starting the csf installation in a node login to the main server (host server) and check whether the following modules are inserted in to the kernel

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ipt_conntrack
ipt_LOG
ipt_owner
ipt_state
ip_conntrack_ftp
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You can check it as follows

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# lsmod |grep -i <module-name>
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If not please insert these modules into the kernel.

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#modprob <module-name>
eg: modprob ipt_conntrack
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Now add these modules to iptable configuration as follows.

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# vi /etc/sysconfig/iptables-config
Add the following in this file
IPTABLES_MODULES=”ipt_conntrack ipt_LOG ipt_owner ipt_state ip_conntrack_ftp”
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Now edit the vps configuration file from /etc/sysconfig/vz-scripts/ Let 101 is the VEID, add the above inserted modules in to the IPTABLE section in this configuration file.

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# vi /etc/sysconfig/vz-scripts/101.conf
IPTABLES=”iptable_filter iptable_mangle ipt_limit ipt_multiport ipt_tos ipt_TOS ipt_REJECT ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_LOG ipt_length ip_conntrack ipt_state
iptable_nat ip_nat_ftp ipt_owner ip_conntrack_ftp”
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Here we completed the main vps server configuration . So now reboot the child node (not main server) as follows

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# vzctl restart <veid>

eg: vzctl restart 101

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ii) Vps node configuration.

Now ssh /enter your child vps node

Now download and install the csf . You can download the csf fromhere

Before restarting the csf let us do some configurations as follows , Edit the file /etc/csf/csf.conf .Then set the following variables

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ETH_DEVICE = “venet0″ #from ifconfig you can see the n/w device
MONOLITHIC_KERNEL = “1″
VERBOSE = “0″ # will disable the verbose output during start
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Now start the csf and lfd .

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/etc/init.d/csf start

/etc/init.d/lfd start

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Note: If it is cpanel server go to whm and configure the firewall settings

Enjoy it

Nice discussion going on slashdot.org about performance differences of xen and openVZ.

An anonymous reader writes Compared to an operating-system-level virtualization technology like OpenVZ, Xen — a hypervisor-level virtualization technology that allows multiple operating systems to be run with and without para-virtualization — trades off performance for much better isolation and security. OpenVZ’s performance advantage due to running virtual containers in a single operating system kernel can be significant. A performance evaluation study (PDF) done by researchers at the University of Michigan and HP labs provides insight into how big a performance penalty Zen pays and what causes the overheads (primarily L2 cache misses).

From the report: “We compare both technologies with a base system in terms of application performance, resource consumption, scalability, low-level system metrics like cache misses and virtualization-specific metrics like Domain-0 consumption in Xen. Our experiments indicate that the average response time can increase by over 400% in Xen and only a modest 100% in OpenVZ as the number of application instances grows from one to four… A similar trend is observed in CPU consumptions of virtual containers.”

Read more from : http://slashdot.org/article.pl?sid=07/05/15/019251

Introduction

The web hosting market provides many opportunities in services for their customers. VPS has a very important place in the overall web hosting marketing. Therefore it is important to consider what type of vps product is to be used in a given service. Today we are going to discuss about what vps control panels are being used by major companies.

What Does VPS Mean?

VPS stands for “Virtual Private Server” and allows multiple Virtual Servers to run within one physical server. Each VPS gets its own portion of resources, which are usually guaranteed to be available to that particular VPS. For instance, imagine that a dedicated server has a specification of 8GB of RAM, and 320GB of hard disc. In these terms 256mb of RAM and 10 GB could be guaranteed to be available to a specific VPS. That would mean that regardless of what resources the other VPS’s on the same server are using, that amount of RAM and hard disc will be available for use.

Another very important point to note is that every running at the same server is independent from each other. Each has its own file system or operating system so a VPS can’t see any of the data of other VPS. For this reason each VPS has its own server load, can be rebooted individually, and so on. Basically it can be treated as a dedicated server by the end user.

Source : http://www.sitetoolcenter.com/webmaster-resource/vps.php

Read more…

A virtual private server (VPS, also referred to as Virtual Dedicated Server or VDS) is a method of partitioning a physical server computer into multiple servers such that each has the appearance and capabilities of running on its own dedicated machine. Each virtual server can run its own full-fledged operating system, and each server can be independently rebooted

The practice of partitioning a single server so that it appears as multiple servers has long been common practice in mainframe computers, but has seen a resurgence lately with the development of virtualization software and technologies for other architectures.