To run this code successfully you must have the permission on the SharePoint farm and site collection administration.
Create the Shared folder on your server and set the permission to "Everyone" on the folder.
SPSecurity.RunWithElevatedPrivileges(delegate()
{
SPWebApplication webApps = SPWebApplication.Lookup(new Uri("http://webapplicationUrl/"));
SPSiteCollection sites = webApps.Sites;
sites.Backup(SPContext.Current.Site.Url, @"\\Server\\SiteBackUp\\backup.dat", false);
});
After this ensure your backup file work as expected by restoring the site
using powershell command
Restore-SPSite -Identity http:/site/sites/restoreSite -Path d:\backup.dat -DatabaseServer database
serverName -DatabaseName WSS_Content -Force
Alternatively you can also use Restore method of SPSiteCollection method.
SPSiteCollection Class