squid : Optimising Web Delivery Virtual Router Redundancy Protocol The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork. VRRP provides information on the state of a router, not the routes processed and exchanged by that router. Each VRRP instance is limited, in scope, to a single subnet. It does not advertise IP routes beyond that subnet or affect the routing table in any way. VRRP can be used in Ethernet, MPLS and token ring networks with Internet Protocol Version 4 (IPv4), as well as IPv6. Implementation[edit] A virtual router must use 00-00-5E-00-01-XX as its Media Access Control (MAC) address. Routers have a priority of between 1-255 and the router with the highest priority will become the master. The default priority is 100 for backups and 255 for a master. Elections of master routers[edit]
dev A ZODB storage for replication using RAID techniques. Latest Version: 1.0b8 The ZEO RAID storage is a storage intended to make ZEO installations more reliable by applying techniques as used in harddisk RAID solutions. The implementation is intended to make use of as much existing infrastructure as possible and provide a seamless and simple experience on setting up a reliable ZEO server infrastructure. Note: We use typical RAID terms to describe the behaviour of this system. The ZEO RAID storage is a proxy storage that works like a RAID controller by creating a redundant array of ZEO servers. Therefore, up to N-1 out of N ZEO servers can fail without interrupting. It is intended that any storage can be used as a backend storage for a RAID storage, although typically a ClientStorage will be the direct backend. The RAID storage could (in theory) be used directly from a Zope server. For this, we leverage the normal ZEO server implementation and simply use a RAID storage instead of a FileStorage.
Json.NET - Home Modèle OSI Un article de Wikipédia, l'encyclopédie libre. Histoire[modifier | modifier le code] Le Modèle OSI a été conçu dans les années 1970, sur fond de rivalités entre trois architectures de conceptions différentes : la DSA lancée par CII-Honeywell-Bull innove dans l'informatique distribuée en mettant en avant les mini-ordinateurs Mitra 15 puis Mini 6, tandis que Decnet, de DEC, et SNA d'IBM donnent une plus grande place au site central, contrôlant l’ensemble des ressources matérielles et logicielles, les utilisateurs y accédant pour une "session" via des terminaux passifs. Hubert Zimmermann, recruté en 1971 à l'IRIA par Louis Pouzin pour développer le Datagramme, technologie qui suscite un enthousiasme international [1], appuyée par la CII[2]. Aperçu[modifier | modifier le code] Le modèle de baseArchitecture de sécuritéDénomination et adressageCadre général de gestion Le texte de la norme proprement dite est très abstrait car il se veut applicable à de nombreux types de réseaux. Contrôle de flux
Tutorial — ZODB 3.10.3 documentation This tutorial is intended to guide developers with a step-by-step introduction of how to develop an application which stores its data in the ZODB. Introduction¶ To save application data in ZODB, you’ll generally define classes that subclass persistent.Persistent: # account.py import persistent class Account(persistent.Persistent): def __init__(self): self.balance = 0.0 def deposit(self, amount): self.balance += amount def cash(self, amount): assert amount < self.balance self.balance -= amount This code defines a simple class that holds the balance of a bank account and provides two methods to manipulate the balance: deposit and cash. Subclassing Persistent provides a number of features: Note that we put the class in a named module. Installation¶ Before being able to use ZODB we have to install it. Creating Databases¶ When a program wants to use the ZODB it has to establish a connection, like any other database. ZODB has a pluggable storage framework. Storing objects¶ Containers and search¶
Getting Started With The PayPal API Advertisement PayPal is the most popular platform for receiving online payments today. The ease of opening a PayPal account and receiving payments compared to opening a merchant account with a traditional payment gateway is probably the number one reason for its popularity, with a close second being the comprehensive API that PayPal provides for its payment services. Disclaimer: PayPal’s API is among the worst I’ve ever had to deal with. The Different Payment Options PayPal offers a variety of payment options, which might be confusing at first: Express Checkout The premier PayPal service. This list is not comprehensive, but it covers the main payment options (see the API documentation for more). Making API Requests PayPal supports two main formats over HTTP: NVP and SOAP. Each of the API methods has different parameters, but they all share some basic parameters, which are used to identify the API account and sign the transaction. Requests are made over HTTPS. Express Checkout 1. 2. 3.
4. LVS: Ipvsadm and Schedulers ipvsadm is the user code interface to LVS. The scheduler is the part of the ipvs kernel code which decides which realserver will get the next new connection. There are patches for ipvsadm You use ipvsadm from the command line (or in rc files) to setup: - services/servers that the director directs (e.g. http goes to all realservers, while ftp goes only to one of the realservers). You use can also use ipvsadm to add services: add a service with weight >0 shutdown (or quiesce) services: set the weight to 0. On the director, the entries for each connection are stored in a hash table (number of buckets set when compiling ipvsadm). We would like to use LVS in a system where 700Mbit/s traffic is flowing through it. Ratz 22 Nov 2006 If you use LVS-DR and your squid caches have a moderate hit rate, the amount of RAM you'll need to load balance 420'000 connections is: 4.3. sysctl documentation the sysctl for ipvs will be in Documentation/networking/ipvs-sysctl.txt for 2.6.18 (hopefully). Horms Ratz
ned Productions - Setting up a dedicated low end Plone ZEO cluster 3/3 [Written Summer 2009] This is the third part of my experiences in setting up a low-end server cluster - refer here for the first part on selecting a VPS and configuring it and refer here for the second part on squeezing the Plone Content Management System onto a ridiculously low end VPS. At the time of writing (Summer 2009), my 256Mb Xen based VPS has been successfully handling my email and providing two Plone based websites for eight months now - indeed, my two guides above have proved most popular with the internet readership. I guess that people find them useful because they contain a lot of information in one place which takes ages to find elsewhere. However as in all healthy things, needs grow especially as I lay the foundations for my new businesses. And besides, and what is very germane especially here, given my current financial situation of unemployment and being (still!) Now Plone is a most interesting case. Before we begin, the OVH RPS mostly dedicated server ... 1a. 1b. 2. #!