{"id":31952,"date":"2026-10-06T22:10:37","date_gmt":"2026-10-06T20:10:37","guid":{"rendered":"https:\/\/www.wedoback.com\/?page_id=31952"},"modified":"2026-10-07T11:00:07","modified_gmt":"2026-10-07T09:00:07","slug":"business-application-during-an-outage","status":"publish","type":"page","link":"https:\/\/www.wedoback.com\/en\/guides\/drp-bcp\/business-application-during-an-outage\/","title":{"rendered":"How do you keep a business application available during an outage?"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"31952\" class=\"elementor elementor-31952 elementor-31583\" data-elementor-post-type=\"page\">\n\t\t\t\t<div class=\"elementor-element elementor-element-5e67a34 e-con-full wdb-g e-flex e-con e-parent\" data-id=\"5e67a34\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-76864d2 e-con-full wdb-g-hero e-flex e-con e-parent\" data-id=\"76864d2\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-c5cf214 e-con-full wdb-g-hero-in e-flex e-con e-parent\" data-id=\"c5cf214\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-f5645bc elementor-widget elementor-widget-text-editor\" data-id=\"f5645bc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"wdb-g-crumb\"><a href=\"\/en\/\">Home<\/a><span>\u203a<\/span><a href=\"\/en\/guides\/\">Guides<\/a><span>\u203a<\/span><a href=\"\/en\/guides\/drp-bcp\/\">DRP and BCP<\/a><\/p><p class=\"wdb-g-pill\" style=\"--pill:#2fc7a0\">DRP and BCP<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7ad7c7b elementor-widget elementor-widget-heading\" data-id=\"7ad7c7b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">How do you keep a business application available during an outage?<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-787c8f9 elementor-widget elementor-widget-text-editor\" data-id=\"787c8f9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"wdb-g-lead\">A business application remains available during an outage if a second instance, already up to date and already reachable from workstations, takes over without each user having to change a setting. If the standby exists but nobody knows how to connect to it, the application is technically \u201csaved\u201d and in practice down.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c17df99 elementor-widget elementor-widget-text-editor\" data-id=\"c17df99\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p class=\"wdb-g-meta\"><span>Updated in <b>October 2026<\/b><\/span><span><b>3 min<\/b> read<\/span><span><b>4<\/b> sources cited<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-475f5d3 e-con-full wdb-g-body e-flex e-con e-parent\" data-id=\"475f5d3\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-86bc100 e-con-full wdb-g-grid e-flex e-con e-parent\" data-id=\"86bc100\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-d5f186d e-con-full wdb-g-article e-flex e-con e-parent\" data-id=\"d5f186d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-0aa1fdf elementor-widget elementor-widget-text-editor\" data-id=\"0aa1fdf\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"wdb-g-key\"><h2>Key points<\/h2><ul><li>Four conditions: <strong>consistent data<\/strong>, a <strong>properly sized<\/strong> standby, a <strong>network path<\/strong> ready to use, a <strong>business check<\/strong>.<\/li><li>The database must be backed up using a method that understands it (transaction log, quiescing), not as plain files.<\/li><li>Keeping the same IP address is more transparent than a DNS change, but requires equipment still working on site.<\/li><li>Check the software <strong>licence<\/strong> on the standby environment before the outage.<\/li><li>If the four conditions are not met, call it a DRP and write down the degraded mode.<\/li><\/ul><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-56d6345 elementor-widget elementor-widget-text-editor\" data-id=\"56d6345\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>The four conditions<\/h2><p><strong>The data is consistent.<\/strong> The application and its database must be copied together, in a state the database engine is willing to open. A file copy taken in the middle of a write may start on a database that the vendor will consider corrupt. The backup or replication tool must understand the database (quiescing, transaction log), not just the disk. For SQL Server, Microsoft also recommends storing backups on a physical location separate from the database files, and points out that you do not have a restore strategy until you have restored a copy on a test system and checked its integrity.<\/p><p><strong>The standby is sized for real work, not just to \u201cshow that it starts\u201d.<\/strong> An instance too small for ten concurrent users creates a software outage in place of the hardware outage.<\/p><p><strong>The network path is ready.<\/strong> Two common techniques:<\/p><ul><li>keep the same IP address as seen by workstations, thanks to on-site equipment that redirects to the standby;<\/li><li>change a DNS name, accepting the propagation delay and workstation caches.<\/li><\/ul><p>The first is more transparent. It requires an agent or appliance still working on site. If the entire site is destroyed (fire), there is no local agent any more: remote users then go through a standby public address, provided it has been reserved and tested. A site-level BCP and a single-server BCP are not prepared in the same way.<\/p><p><strong>Someone checks the application, not just the system.<\/strong> Opening the login screen is not enough. An authorised user performs a usual task: look up a case file, issue a document, print.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-1a080a1 elementor-widget elementor-widget-text-editor\" data-id=\"1a080a1\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Comparing the two network paths<\/h2><table><thead><tr><th><\/th><th>Same IP address via on-site equipment<\/th><th>DNS name change<\/th><\/tr><\/thead><tbody><tr><td>Action on workstations<\/td><td>None<\/td><td>Sometimes clearing the cache or restarting<\/td><\/tr><tr><td>Failover time<\/td><td>Short<\/td><td>Depends on the lifetime (TTL) of DNS records<\/td><\/tr><tr><td>Works if the site is destroyed<\/td><td>No<\/td><td>Yes, if remote access is ready<\/td><\/tr><tr><td>Point to watch<\/td><td>The on-site equipment must survive<\/td><td>Addresses hard-coded in software<\/td><\/tr><\/tbody><\/table>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-da32154 elementor-widget elementor-widget-text-editor\" data-id=\"da32154\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Before the outage: the checklist<\/h2><ul><li>The database backup method is documented and has already produced a successful restore.<\/li><li>The standby size has been validated against the expected number of users.<\/li><li>The network path has been tested from an ordinary workstation, not from the administrator&#8217;s workstation.<\/li><li>The licence works on the standby.<\/li><li>A business user performed a real task on the standby during the last test. See <a href=\"\/en\/guides\/drp-bcp\/how-to-test-a-drp\/\">How do you test a DRP?<\/a>.<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ec6cedd elementor-widget elementor-widget-text-editor\" data-id=\"ec6cedd\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Degraded mode<\/h2><p>If the four conditions are not met, the honest approach is to call it a DRP (recovery after an interruption) and to write down the degraded mode: which tasks can wait, which are noted on paper, who re-enters them afterwards. An \u201cessential\u201d application whose degraded mode can last half a day does not necessarily need a standby running all year round. The ANSSI, France&#8217;s national cybersecurity agency, recommends planning these workarounds in advance, because a cyber-related crisis can last several weeks.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7ddfe3b elementor-widget elementor-widget-text-editor\" data-id=\"7ddfe3b\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Licences and software vendors<\/h2><p>Some business software ties the licence to a hardware identifier, or prohibits external hosting. Check this before the outage. A standby that starts and then shuts down for lack of a licence is not a standby.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-503bece elementor-widget elementor-widget-text-editor\" data-id=\"503bece\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"wdb-g-brand\"><h2>At WeDoBack<\/h2><p>The <a href=\"\/en\/bcp-offer\/\">BCP<\/a> is designed for this case: cloud instances running permanently, an agent on the customer&#8217;s network, an IPsec VPN link, and takeover with no change of IP address. It therefore keeps the application reachable from on-site workstations as long as the agent and the local network exist. For the application database to be up to date on the instance, and for data entered during the outage to return to the repaired server, a specific replication or synchronisation process is needed: it is not built in, and WeDoBack can set it up on <a href=\"\/en\/quotation\/\">quotation<\/a>. Instances start at 50.22 \u20ac excl. VAT per month, storage at 8.75 \u20ac excl. VAT per month for 50 GB. If the building is destroyed, this local mechanism is no longer enough: public addresses and remote access are needed, which fall rather under the <a href=\"\/en\/drp-offer\/\">DRP<\/a> with public IP addresses (0.54 \u20ac excl. VAT per address per month). WeDoBack backs up SQL Server, Exchange and business software, and restores the server and the application if they were backed up consistently. It does not fix a database that was copied haphazardly: the database backup method is part of the implementation and must be tested beforehand.<\/p><div class=\"wdb-g-btns\"><a class=\"wdb-g-btn wdb-g-btn-primary\" href=\"\/en\/bcp-offer\/\">Discover the BCP<\/a><a class=\"wdb-g-btn wdb-g-btn-ghost\" href=\"\/en\/quotation\/\">Request a quote<\/a><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e8976f5 elementor-widget elementor-widget-text-editor\" data-id=\"e8976f5\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"wdb-g-faq\"><h2>Frequently asked questions<\/h2><details><summary>Can database files be copied like any other files?<\/summary><p>That is not enough. A copy taken in the middle of a write can produce a database that the engine will refuse to open. You need a backup that understands the database (native backup, transaction log or quiescing). Microsoft also points out that a restore strategy only exists once the backups have been tested on a test system.<\/p><\/details><details><summary>Does the standby need to be as powerful as the production server?<\/summary><p>It must handle the number of concurrent users expected during the outage. An undersized standby turns a hardware failure into a performance failure. A somewhat more modest standby can be acceptable if the degraded mode reduces the number of users, provided this has been measured.<\/p><\/details><details><summary>What happens if the whole building is destroyed?<\/summary><p>Mechanisms that rely on on-site equipment (agent, appliance) disappear with the site. Users must then reach the standby from outside, through a public address and remote access reserved and tested in advance. This is a different scenario from a single server failure.<\/p><\/details><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-804bd67 elementor-widget elementor-widget-text-editor\" data-id=\"804bd67\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Further reading<\/h2><div class=\"wdb-g-related\"><a href=\"\/en\/guides\/drp-bcp\/what-is-a-bcp\/\"><small>DRP and BCP<\/small>What is a BCP?<\/a><a href=\"\/en\/guides\/drp-bcp\/critical-server-continuity\/\"><small>DRP and BCP<\/small>How do you ensure continuity for a critical server?<\/a><a href=\"\/en\/guides\/drp-bcp\/outsourced-bcp-pros-and-cons\/\"><small>DRP and BCP<\/small>Outsourced BCP: pros and cons<\/a><a href=\"\/en\/guides\/drp-bcp\/how-to-test-a-drp\/\"><small>DRP and BCP<\/small>How do you test a DRP?<\/a><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-c9be1c6 elementor-widget elementor-widget-text-editor\" data-id=\"c9be1c6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"wdb-g-sources\"><h2>Sources<\/h2><p class=\"wdb-g-src-date\">Documents consulted in October 2026.<\/p><ol><li><a href=\"https:\/\/learn.microsoft.com\/en-us\/sql\/relational-databases\/backup-restore\/back-up-and-restore-of-sql-server-databases?view=sql-server-ver17\" target=\"_blank\" rel=\"noopener\">Back up and Restore of SQL Server Databases<\/a> \u2014 Microsoft Learn<\/li><li><a href=\"https:\/\/messervices.cyber.gouv.fr\/documents-guides\/anssi-guide-gestion_crise_cyber.pdf\" target=\"_blank\" rel=\"noopener\">Cyber crisis: keys to operational and strategic management (December 2021)<\/a> \u2014 ANSSI<\/li><li><a href=\"https:\/\/www.wedoback.com\/offre-pca\/\" target=\"_blank\" rel=\"noopener\">BCP offer: immediate business continuity<\/a> \u2014 WeDoBack<\/li><li><a href=\"https:\/\/www.wedoback.com\/offre-pra\/\" target=\"_blank\" rel=\"noopener\">DRP offer: recovery after a disaster<\/a> \u2014 WeDoBack<\/li><\/ol><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-c9c7c1a e-con-full wdb-g-aside e-flex e-con e-parent\" data-id=\"c9c7c1a\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-f9be109 elementor-widget elementor-widget-text-editor\" data-id=\"f9be109\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<nav class=\"wdb-g-toc\" aria-label=\"Table of contents\"><p>On this page<\/p><ol><\/ol><\/nav>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6319b25 elementor-widget elementor-widget-text-editor\" data-id=\"6319b25\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"wdb-g-card\"><h3>Planning a backup, DRP or BCP project?<\/h3><p>More than 20 years of experience protecting business data.<\/p><a class=\"wdb-g-btn wdb-g-btn-primary\" href=\"\/en\/quotation\/\">Request a quote<\/a><a class=\"wdb-g-tel\" href=\"tel:+33972507828\">+33 9 72 50 78 28<\/a><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-083ae41 e-con-full wdb-g-cta e-flex e-con e-parent\" data-id=\"083ae41\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-facd81f e-con-full wdb-g-cta-in e-flex e-con e-parent\" data-id=\"facd81f\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-0ff0478 elementor-widget elementor-widget-text-editor\" data-id=\"0ff0478\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<h2>Protect your data with WeDoBack<\/h2><p>Encrypted offsite backup, immutable storage, DRP and BCP: tell us about your servers and we will recommend the right combination.<\/p><div class=\"wdb-g-btns\"><a class=\"wdb-g-btn wdb-g-btn-primary\" href=\"\/en\/quotation\/\">Request a quote<\/a><a class=\"wdb-g-btn wdb-g-btn-ghost\" href=\"\/en\/offers-and-prices\/\">See offers and prices<\/a><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":31777,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"elementor_header_footer","meta":{"_seopress_titles_title":"Business application uptime during an outage | WeDoBack","_seopress_titles_desc":"A business application stays available if its standby is already reachable, with consistent data, without reconfiguring workstations one by 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