Equalizer

Coyote Point's Equalizer line is a series of devices that are installed in front of the server farm (between the servers and the Internet access point) and provide load balancing capabilities among the multiple servers at layer 4 or layer 4-7 levels. Devices are available supporting from 64 to an unlimited number of virtual server clusters, each cluster containing from 16 to 512 physical servers. Each of the devices is rack-mountable, can be installed in redundant pair configurations supporting hot-backup functionality, and is RoHS compliant.

Load balancing algorithm features common to all of the devices include support for least connections, weighted least connections, round robin, weighted round robin, and direct server measurements; the latter of which is facilitated through optional server agents. The devices support "most" UDP and TCP/IP-based protocols; including HTTP, SSL, FTP, POP, IMAP, SMTP, etc. The E350si and later devices also support Layer 7 content-based switching options and the use of cookies, "sticky connections," and header match rules to maintain persistent session states. Server health is determined by ICMP and TCP checks (layer 4) or, in the 350si and higher, L7 content verification. Traffic is automatically redirected away from failed servers.

Management of the devices is via a Web-based interface or a CLI (serial, SSH). The latest software release additionally supports SNMP communications.

Individual models available in the Equalizer line include:

- E250si: Includes 5 10/100 Ethernet ports, supporting direct attachment of up to 4 servers; an overall maximum of 1024 servers can be balanced by attaching it to switches. The E250si supports up to 64 virtual server clusters, each of which can contain up to 16 physical servers. Throughput is listed at 60 Mb/sec, with up to 100,000 concurrent connections supported.

- E350si: With 8 10/100 Ethernet ports and a single 10/100/1000 port. The E350si can drive an unlimited number of virtual server clusters, each of which can include up to 32 physical servers. Throughput is listed at 775 Mb/sec, with up to 2 million concurrent connections supported.

- E450si: With 16 10/100 Ethernet ports and a single 10/100/1000 port. The E450si can also drive an unlimited number of virtual server clusters, each of which can include up to 128 physical servers. Throughput is listed at 800 Mb/sec, with up to 8 million concurrent connections supported.

- E550si: The E550si is billed as an enterprise class device, boasting 21 10/100/1000 ports and driving an unlimited number of virtual server clusters, each of which can include up to 512 physical servers. The E550si can deliver up to 830 Mb/sec in throughput, up to a maximum 12 million concurrent connections.

- E650si: The newest model in the line. The E550si is similar to the E550si, except that it bundles all of the vendor's optional add-on components (described below), including the new Equalizer VLB VMware integration software.

Available as optional add-ons for the Equalizer devices are the vendor's Xcel SSL acceleration module; The Express Compression module (E350si+); and Envoy, which facilitates global load balancing amongst geographically distributed data centers (also E350si+). And new to the vendor's product line is the initial version of their Equalizer VLB software, which leverages the information provided by the VMware management API (memory in use by a VM, CPU utilization, etc.) to monitor and manage the delivery of traffic to virtual servers. Equalizer VLB is currently a free beta download for E350si and higher Equalizers, and is automatically included in the new E650si Equalizer. The vendor notes that a later version of the Equalizer VLB offering (due in the latter part of 2008) will be available as a software license and will provide stronger integration with virtual machines, allowing VLB, for example, to instruct VMware as to when to move VMs to other resources, shut them down/power them up, etc.

With the exception of the new E650si, the Equalizer devices are available now, with pricing ranging from $3,995 to $10,995. The E650si is expected to be available in May with a suggested retail price of $13,449.

Contact Coyote Point Systems for further information.