http://kb.linuxvirtualserver.org/api.php?action=feedcontributions&user=Ckujau&feedformat=atomLVSKB - User contributions [en]2024-03-28T19:49:53ZUser contributionsMediaWiki 1.26.2http://kb.linuxvirtualserver.org/wiki?title=FAQ&diff=5810FAQ2009-07-25T23:00:07Z<p>Ckujau: how to check for IPVS support w/o installing tools/modules.</p>
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<div>== General ==<br />
=== What's LVS? ===<br />
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[[LVS]] stands for Linux Virtual Server, which is a highly scalable and highly available server built on a cluster of real servers, with the [[load balancer]] running on the Linux operating system. Users interact as if it were a single virtual server.<br />
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=== Is LVS software free? ===<br />
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Yes! All [[LVS]] software is released under the [http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)].<br />
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=== Is there a FreeBSD port of LVS software? ===<br />
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Yes, there is a FreeBSD port of IPVS, which supports the [[LVS/DR]] and [[LVS/TUN]] methods now. See [http://dragon.linux-vs.org/~dragonfly/htm/lvs_freebsd.htm the LVS On FreeBSD page] for more information.<br />
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=== Does LVS cluster support Linux servers only? ===<br />
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No, real servers can almost run any operating systems in a LVS cluster, such as Linux, BSDs, Solaris, and Windows. [[LVS/NAT]] balances servers of the operating systems having TCP/IP support, [[LVS/TUN]] requires servers having IP Tunneling protocol, and [[LVS/DR]] requires servers having a non-arp device. Almost all the modern operating systems support non-arp device.<br />
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== Performance ==<br />
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=== How is the concurrent processing performance of current LVS software? ===<br />
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The ultimate performance of LVS depends on hardware that LVS runs on. An ordinary box with a single Pentium III processor and 100Mbps NIC card running [[LVS/DR]] can handle about 10,000 connections per second for web service. We have heard that a powerful box with good hardware and kernel tuning achieved 50,000 connections per second.<br />
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=== Can LVS handle more than 1 million simultaneous connections? ===<br />
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Yes, LVS can handle much more than 1 million simultaneous connections. One connection just costs 128 bytes in the LVS box, so an LVS box with 1G memory can handle more than 8 million simultaneous connections.<br />
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== Setup ==<br />
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=== Is there a quick guide to setup LVS ===<br />
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Yes, please check the article [[Mini Mini Howto]], which covers setting up LVS quickly on Linux distributions of Fedora Core 4 or later.<br />
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=== How do I check to see if my kernel has IPVS enabled? ===<br />
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Try to run <tt>"modprobe ip_vs"</tt> and try to see if there is <tt>/proc/net/ip_vs</tt>. If so, your kernel has [[IPVS]] enabled. You can also run <tt>"cat /proc/net/ip_vs"</tt> or <tt>"ipvsadm -Ln"</tt> to see the version number of [[IPVS]].<br />
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<pre><br />
[root@lb4 root]# ipvsadm -Ln<br />
IP Virtual Server version 1.0.11 (size=65536)<br />
Prot LocalAddress:Port Scheduler Flags<br />
-> RemoteAddress:Port Forward Weight ActiveConn InActConn<br />
...<br />
</pre><br />
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You could also check your current kernel config (<tt>/proc/config{.gz}</tt> or somewhere in <tt>/boot</tt>) if <tt>CONFIG_IP_VS</tt> is set (located under <tt>Networking support->Networking options->Netfilter</tt> when using <tt>make menuconfig</tt> to configure your kernel).<br />
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=== How to compile ipvsadm on difficult Linux distributions ===<br />
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[[Ipvsadm]] is the tool to set up, maintain or inspect the [[IPVS]] table in the Linux kernel. See the article [[compiling ipvsadm on different Linux distributions]] for detailed information.<br />
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== Statistics ==<br />
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=== How do i get counters from ipvsadm in order to create graphs from? ===<br />
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'''Answer 1:'''<br />
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The current kernel 2.6 version of ipvsadm (v1.24) supports<br />
ipvsadm --list --stats --numeric --exact<br />
which gives you non-human-readable counters for Connections, Packets and Bytes for each Service Address and Realserver.<br />
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'''Answer 2:'''<br />
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Install [http://oss.oetiker.ch/rrdtool/ RRDtool] and preferabely [http://www.cacti.net/ Cacti] onto a host of your choice. From your favorite Linux distribution, install the [http://www.net-snmp.org/ Net-SNMP daemon] onto the Loadbalancer host. Apply the [[Net-SNMP-LVS-Module]] to the Net-SNMP daemon. Using RRDtool and/or cacti you may query the Loadbalancer and create all kind of graphs using the statistics the Loadbalancers IPVS-module delivers.<br />
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[[Category:LVS Handbook]]</div>Ckujau