What is causing intermittent connections problems from web server to sql server 2008 r2?SQL Server 2008 Remote AccessNetwork Load Balancing, intermittent port problem on Windows Server 2008Connecting SQL 2008 and Web server 2008 using directly connected Ethernet cable on 2nd network cardsSynch SQL 2008 with failover server?Double hop problem with sql server 2008Implementing Automatic failover with SQL Server 2008 R2 Web EditionSQL Server 2008 Web edition - access from another IIS?.NET + Connection to SQL Server 2008 R2How do you begin to diagnose intermittent SQL Server connection errors?

Print the new site header

Is a sequel allowed to start before the end of the first book?

Does cooling a potato change the nature of its carbohydrates?

Checking if argument is a floating point without breaking on control sequences in argument

How much steel armor can you wear and still be able to swim?

Boundaries and Buddhism

Harmonic Series Phase Difference?

How to prevent cables getting intertwined

Co-worker is now managing my team. Does this mean that I'm being demoted?

...and then she held the gun

How did the European Union reach the figure of 3% as a maximum allowed deficit?

How can I detect if I'm in a subshell?

How to address players struggling with simple controls?

How can caller ID be faked?

Should I email my professor to clear up a (possibly very irrelevant) awkward misunderstanding?

Justifying Affordable Bespoke Spaceships

Would a 7805 5v regulator drain a 9v battery?

Having some issue with notation in a Hilbert space

How useful is the GRE Exam?

You may find me... puzzling

What is "dot" sign in •NO?

Is the infant mortality rate among African-American babies in Youngstown, Ohio greater than that of babies in Iran?

Basic power tool set for Home repair and simple projects

Bash function: Execute $@ command with each argument in sequence executed separately



What is causing intermittent connections problems from web server to sql server 2008 r2?


SQL Server 2008 Remote AccessNetwork Load Balancing, intermittent port problem on Windows Server 2008Connecting SQL 2008 and Web server 2008 using directly connected Ethernet cable on 2nd network cardsSynch SQL 2008 with failover server?Double hop problem with sql server 2008Implementing Automatic failover with SQL Server 2008 R2 Web EditionSQL Server 2008 Web edition - access from another IIS?.NET + Connection to SQL Server 2008 R2How do you begin to diagnose intermittent SQL Server connection errors?






.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty height:90px;width:728px;box-sizing:border-box;








0















We have 4 API servers and 2 web servers that connect to a SQL 2008 R2 server. Recently we've noticed that the web servers sometimes can't find the SQL server. This doesn't happen for every connection, but it does happen several times per minute. All the servers are on Windows 2008 R2, and connect to the DB via TCP. We've verified that the DB is reachable, and in fact, the API servers don't have any problems connecting to the DB.



Because the connection problems are intermittent it is proving difficult to troubleshoot. We've verified that the firewall is not blocking the connection, and that the maximum number of connections is not being reached (max is the default of 32767, and our average connection count at any given time is around 1000).



What might be causing these irregular connection problems?










share|improve this question




























    0















    We have 4 API servers and 2 web servers that connect to a SQL 2008 R2 server. Recently we've noticed that the web servers sometimes can't find the SQL server. This doesn't happen for every connection, but it does happen several times per minute. All the servers are on Windows 2008 R2, and connect to the DB via TCP. We've verified that the DB is reachable, and in fact, the API servers don't have any problems connecting to the DB.



    Because the connection problems are intermittent it is proving difficult to troubleshoot. We've verified that the firewall is not blocking the connection, and that the maximum number of connections is not being reached (max is the default of 32767, and our average connection count at any given time is around 1000).



    What might be causing these irregular connection problems?










    share|improve this question
























      0












      0








      0








      We have 4 API servers and 2 web servers that connect to a SQL 2008 R2 server. Recently we've noticed that the web servers sometimes can't find the SQL server. This doesn't happen for every connection, but it does happen several times per minute. All the servers are on Windows 2008 R2, and connect to the DB via TCP. We've verified that the DB is reachable, and in fact, the API servers don't have any problems connecting to the DB.



      Because the connection problems are intermittent it is proving difficult to troubleshoot. We've verified that the firewall is not blocking the connection, and that the maximum number of connections is not being reached (max is the default of 32767, and our average connection count at any given time is around 1000).



      What might be causing these irregular connection problems?










      share|improve this question














      We have 4 API servers and 2 web servers that connect to a SQL 2008 R2 server. Recently we've noticed that the web servers sometimes can't find the SQL server. This doesn't happen for every connection, but it does happen several times per minute. All the servers are on Windows 2008 R2, and connect to the DB via TCP. We've verified that the DB is reachable, and in fact, the API servers don't have any problems connecting to the DB.



      Because the connection problems are intermittent it is proving difficult to troubleshoot. We've verified that the firewall is not blocking the connection, and that the maximum number of connections is not being reached (max is the default of 32767, and our average connection count at any given time is around 1000).



      What might be causing these irregular connection problems?







      windows-server-2008 sql-server web-server sql-server-2008






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Aug 18 '10 at 22:07







      Aaron Lewis



























          2 Answers
          2






          active

          oldest

          votes


















          0














          So these DB servers are on another network (via the firewall)? If so take a look at the ARP cache on the web and DB servers at the time the problem occurs and look at the ARP table on the firewall when the problem occurs. The web servers should have the MAC address of the firewall for the DB server's ip address in their cache, the DB servers should have the MAC address of the firewall for the web server's ip address in their cache, and the firewall should have the MAC address for the DB server's ip address and the MAC address for the web server's ip address in it's cache. Make sure that the firewall ARP table shows the MAC adresses for the servers listed on the appropriate firewall interface that each server is "connected" to. If that gets you no where then check the ARP table on the switches between the web and DB servers.



          You can also put a network sniffer on the web and DB servers and start a packet capture. When the problem occurs, look at the capture on both ends and see what's happening. You should see traffic from the web servers toward the DB servers (toward the firewall) and from the DB servers to the web servers (toward the firewall). If you do then it's a network problem, if you don't then it's a server problem.




          EDIT



          Also, you can look for any RST packets coming from either end of the connection in your network capture that might be coming from the firewall due to connection timeout settings on the firewall.






          share|improve this answer
































            0














            I'd suggest looking at the NIC statistics -- mainly error counts, whether there's any offloading to a TOE module happening, and whether the web servers' link to the switch (or another net device) is getting saturated. Also the output of 'netstat -ano' -- it's possible you'll get errors if the entire ephemeral port range (49152-65535 by default on Windows 2008) is in use on the web servers.



            Being intermittently unable to connect to SQL can have myriad causes from hardware to connection pooling problems, so if you could post the error message that's being logged or displayed (assuming there is one), that might give people a better idea of what's wrong.






            share|improve this answer























              Your Answer








              StackExchange.ready(function()
              var channelOptions =
              tags: "".split(" "),
              id: "2"
              ;
              initTagRenderer("".split(" "), "".split(" "), channelOptions);

              StackExchange.using("externalEditor", function()
              // Have to fire editor after snippets, if snippets enabled
              if (StackExchange.settings.snippets.snippetsEnabled)
              StackExchange.using("snippets", function()
              createEditor();
              );

              else
              createEditor();

              );

              function createEditor()
              StackExchange.prepareEditor(
              heartbeatType: 'answer',
              autoActivateHeartbeat: false,
              convertImagesToLinks: true,
              noModals: true,
              showLowRepImageUploadWarning: true,
              reputationToPostImages: 10,
              bindNavPrevention: true,
              postfix: "",
              imageUploader:
              brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
              contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
              allowUrls: true
              ,
              onDemand: true,
              discardSelector: ".discard-answer"
              ,immediatelyShowMarkdownHelp:true
              );



              );













              draft saved

              draft discarded


















              StackExchange.ready(
              function ()
              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fserverfault.com%2fquestions%2f172089%2fwhat-is-causing-intermittent-connections-problems-from-web-server-to-sql-server%23new-answer', 'question_page');

              );

              Post as a guest















              Required, but never shown
























              2 Answers
              2






              active

              oldest

              votes








              2 Answers
              2






              active

              oldest

              votes









              active

              oldest

              votes






              active

              oldest

              votes









              0














              So these DB servers are on another network (via the firewall)? If so take a look at the ARP cache on the web and DB servers at the time the problem occurs and look at the ARP table on the firewall when the problem occurs. The web servers should have the MAC address of the firewall for the DB server's ip address in their cache, the DB servers should have the MAC address of the firewall for the web server's ip address in their cache, and the firewall should have the MAC address for the DB server's ip address and the MAC address for the web server's ip address in it's cache. Make sure that the firewall ARP table shows the MAC adresses for the servers listed on the appropriate firewall interface that each server is "connected" to. If that gets you no where then check the ARP table on the switches between the web and DB servers.



              You can also put a network sniffer on the web and DB servers and start a packet capture. When the problem occurs, look at the capture on both ends and see what's happening. You should see traffic from the web servers toward the DB servers (toward the firewall) and from the DB servers to the web servers (toward the firewall). If you do then it's a network problem, if you don't then it's a server problem.




              EDIT



              Also, you can look for any RST packets coming from either end of the connection in your network capture that might be coming from the firewall due to connection timeout settings on the firewall.






              share|improve this answer





























                0














                So these DB servers are on another network (via the firewall)? If so take a look at the ARP cache on the web and DB servers at the time the problem occurs and look at the ARP table on the firewall when the problem occurs. The web servers should have the MAC address of the firewall for the DB server's ip address in their cache, the DB servers should have the MAC address of the firewall for the web server's ip address in their cache, and the firewall should have the MAC address for the DB server's ip address and the MAC address for the web server's ip address in it's cache. Make sure that the firewall ARP table shows the MAC adresses for the servers listed on the appropriate firewall interface that each server is "connected" to. If that gets you no where then check the ARP table on the switches between the web and DB servers.



                You can also put a network sniffer on the web and DB servers and start a packet capture. When the problem occurs, look at the capture on both ends and see what's happening. You should see traffic from the web servers toward the DB servers (toward the firewall) and from the DB servers to the web servers (toward the firewall). If you do then it's a network problem, if you don't then it's a server problem.




                EDIT



                Also, you can look for any RST packets coming from either end of the connection in your network capture that might be coming from the firewall due to connection timeout settings on the firewall.






                share|improve this answer



























                  0












                  0








                  0







                  So these DB servers are on another network (via the firewall)? If so take a look at the ARP cache on the web and DB servers at the time the problem occurs and look at the ARP table on the firewall when the problem occurs. The web servers should have the MAC address of the firewall for the DB server's ip address in their cache, the DB servers should have the MAC address of the firewall for the web server's ip address in their cache, and the firewall should have the MAC address for the DB server's ip address and the MAC address for the web server's ip address in it's cache. Make sure that the firewall ARP table shows the MAC adresses for the servers listed on the appropriate firewall interface that each server is "connected" to. If that gets you no where then check the ARP table on the switches between the web and DB servers.



                  You can also put a network sniffer on the web and DB servers and start a packet capture. When the problem occurs, look at the capture on both ends and see what's happening. You should see traffic from the web servers toward the DB servers (toward the firewall) and from the DB servers to the web servers (toward the firewall). If you do then it's a network problem, if you don't then it's a server problem.




                  EDIT



                  Also, you can look for any RST packets coming from either end of the connection in your network capture that might be coming from the firewall due to connection timeout settings on the firewall.






                  share|improve this answer















                  So these DB servers are on another network (via the firewall)? If so take a look at the ARP cache on the web and DB servers at the time the problem occurs and look at the ARP table on the firewall when the problem occurs. The web servers should have the MAC address of the firewall for the DB server's ip address in their cache, the DB servers should have the MAC address of the firewall for the web server's ip address in their cache, and the firewall should have the MAC address for the DB server's ip address and the MAC address for the web server's ip address in it's cache. Make sure that the firewall ARP table shows the MAC adresses for the servers listed on the appropriate firewall interface that each server is "connected" to. If that gets you no where then check the ARP table on the switches between the web and DB servers.



                  You can also put a network sniffer on the web and DB servers and start a packet capture. When the problem occurs, look at the capture on both ends and see what's happening. You should see traffic from the web servers toward the DB servers (toward the firewall) and from the DB servers to the web servers (toward the firewall). If you do then it's a network problem, if you don't then it's a server problem.




                  EDIT



                  Also, you can look for any RST packets coming from either end of the connection in your network capture that might be coming from the firewall due to connection timeout settings on the firewall.







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited Aug 18 '10 at 23:08

























                  answered Aug 18 '10 at 22:19









                  joeqwertyjoeqwerty

                  97.7k466149




                  97.7k466149























                      0














                      I'd suggest looking at the NIC statistics -- mainly error counts, whether there's any offloading to a TOE module happening, and whether the web servers' link to the switch (or another net device) is getting saturated. Also the output of 'netstat -ano' -- it's possible you'll get errors if the entire ephemeral port range (49152-65535 by default on Windows 2008) is in use on the web servers.



                      Being intermittently unable to connect to SQL can have myriad causes from hardware to connection pooling problems, so if you could post the error message that's being logged or displayed (assuming there is one), that might give people a better idea of what's wrong.






                      share|improve this answer



























                        0














                        I'd suggest looking at the NIC statistics -- mainly error counts, whether there's any offloading to a TOE module happening, and whether the web servers' link to the switch (or another net device) is getting saturated. Also the output of 'netstat -ano' -- it's possible you'll get errors if the entire ephemeral port range (49152-65535 by default on Windows 2008) is in use on the web servers.



                        Being intermittently unable to connect to SQL can have myriad causes from hardware to connection pooling problems, so if you could post the error message that's being logged or displayed (assuming there is one), that might give people a better idea of what's wrong.






                        share|improve this answer

























                          0












                          0








                          0







                          I'd suggest looking at the NIC statistics -- mainly error counts, whether there's any offloading to a TOE module happening, and whether the web servers' link to the switch (or another net device) is getting saturated. Also the output of 'netstat -ano' -- it's possible you'll get errors if the entire ephemeral port range (49152-65535 by default on Windows 2008) is in use on the web servers.



                          Being intermittently unable to connect to SQL can have myriad causes from hardware to connection pooling problems, so if you could post the error message that's being logged or displayed (assuming there is one), that might give people a better idea of what's wrong.






                          share|improve this answer













                          I'd suggest looking at the NIC statistics -- mainly error counts, whether there's any offloading to a TOE module happening, and whether the web servers' link to the switch (or another net device) is getting saturated. Also the output of 'netstat -ano' -- it's possible you'll get errors if the entire ephemeral port range (49152-65535 by default on Windows 2008) is in use on the web servers.



                          Being intermittently unable to connect to SQL can have myriad causes from hardware to connection pooling problems, so if you could post the error message that's being logged or displayed (assuming there is one), that might give people a better idea of what's wrong.







                          share|improve this answer












                          share|improve this answer



                          share|improve this answer










                          answered Jul 3 '11 at 12:15









                          James LJames L

                          3591518




                          3591518



























                              draft saved

                              draft discarded
















































                              Thanks for contributing an answer to Server Fault!


                              • Please be sure to answer the question. Provide details and share your research!

                              But avoid


                              • Asking for help, clarification, or responding to other answers.

                              • Making statements based on opinion; back them up with references or personal experience.

                              To learn more, see our tips on writing great answers.




                              draft saved


                              draft discarded














                              StackExchange.ready(
                              function ()
                              StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fserverfault.com%2fquestions%2f172089%2fwhat-is-causing-intermittent-connections-problems-from-web-server-to-sql-server%23new-answer', 'question_page');

                              );

                              Post as a guest















                              Required, but never shown





















































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown

































                              Required, but never shown














                              Required, but never shown












                              Required, but never shown







                              Required, but never shown







                              Popular posts from this blog

                              Club Baloncesto Breogán Índice Historia | Pavillón | Nome | O Breogán na cultura popular | Xogadores | Adestradores | Presidentes | Palmarés | Historial | Líderes | Notas | Véxase tamén | Menú de navegacióncbbreogan.galCadroGuía oficial da ACB 2009-10, páxina 201Guía oficial ACB 1992, páxina 183. Editorial DB.É de 6.500 espectadores sentados axeitándose á última normativa"Estudiantes Junior, entre as mellores canteiras"o orixinalHemeroteca El Mundo Deportivo, 16 setembro de 1970, páxina 12Historia do BreogánAlfredo Pérez, o último canoneiroHistoria C.B. BreogánHemeroteca de El Mundo DeportivoJimmy Wright, norteamericano do Breogán deixará Lugo por ameazas de morteResultados de Breogán en 1986-87Resultados de Breogán en 1990-91Ficha de Velimir Perasović en acb.comResultados de Breogán en 1994-95Breogán arrasa al Barça. "El Mundo Deportivo", 27 de setembro de 1999, páxina 58CB Breogán - FC BarcelonaA FEB invita a participar nunha nova Liga EuropeaCharlie Bell na prensa estatalMáximos anotadores 2005Tempada 2005-06 : Tódolos Xogadores da Xornada""Non quero pensar nunha man negra, mais pregúntome que está a pasar""o orixinalRaúl López, orgulloso dos xogadores, presume da boa saúde económica do BreogánJulio González confirma que cesa como presidente del BreogánHomenaxe a Lisardo GómezA tempada do rexurdimento celesteEntrevista a Lisardo GómezEl COB dinamita el Pazo para forzar el quinto (69-73)Cafés Candelas, patrocinador del CB Breogán"Suso Lázare, novo presidente do Breogán"o orixinalCafés Candelas Breogán firma el mayor triunfo de la historiaEl Breogán realizará 17 homenajes por su cincuenta aniversario"O Breogán honra ao seu fundador e primeiro presidente"o orixinalMiguel Giao recibiu a homenaxe do PazoHomenaxe aos primeiros gladiadores celestesO home que nos amosa como ver o Breo co corazónTita Franco será homenaxeada polos #50anosdeBreoJulio Vila recibirá unha homenaxe in memoriam polos #50anosdeBreo"O Breogán homenaxeará aos seus aboados máis veteráns"Pechada ovación a «Capi» Sanmartín e Ricardo «Corazón de González»Homenaxe por décadas de informaciónPaco García volve ao Pazo con motivo do 50 aniversario"Resultados y clasificaciones""O Cafés Candelas Breogán, campión da Copa Princesa""O Cafés Candelas Breogán, equipo ACB"C.B. Breogán"Proxecto social"o orixinal"Centros asociados"o orixinalFicha en imdb.comMario Camus trata la recuperación del amor en 'La vieja música', su última película"Páxina web oficial""Club Baloncesto Breogán""C. B. Breogán S.A.D."eehttp://www.fegaba.com

                              Vilaño, A Laracha Índice Patrimonio | Lugares e parroquias | Véxase tamén | Menú de navegación43°14′52″N 8°36′03″O / 43.24775, -8.60070

                              Cegueira Índice Epidemioloxía | Deficiencia visual | Tipos de cegueira | Principais causas de cegueira | Tratamento | Técnicas de adaptación e axudas | Vida dos cegos | Primeiros auxilios | Crenzas respecto das persoas cegas | Crenzas das persoas cegas | O neno deficiente visual | Aspectos psicolóxicos da cegueira | Notas | Véxase tamén | Menú de navegación54.054.154.436928256blindnessDicionario da Real Academia GalegaPortal das Palabras"International Standards: Visual Standards — Aspects and Ranges of Vision Loss with Emphasis on Population Surveys.""Visual impairment and blindness""Presentan un plan para previr a cegueira"o orixinalACCDV Associació Catalana de Cecs i Disminuïts Visuals - PMFTrachoma"Effect of gene therapy on visual function in Leber's congenital amaurosis"1844137110.1056/NEJMoa0802268Cans guía - os mellores amigos dos cegosArquivadoEscola de cans guía para cegos en Mortágua, PortugalArquivado"Tecnología para ciegos y deficientes visuales. Recopilación de recursos gratuitos en la Red""Colorino""‘COL.diesis’, escuchar los sonidos del color""COL.diesis: Transforming Colour into Melody and Implementing the Result in a Colour Sensor Device"o orixinal"Sistema de desarrollo de sinestesia color-sonido para invidentes utilizando un protocolo de audio""Enseñanza táctil - geometría y color. Juegos didácticos para niños ciegos y videntes""Sistema Constanz"L'ocupació laboral dels cecs a l'Estat espanyol està pràcticament equiparada a la de les persones amb visió, entrevista amb Pedro ZuritaONCE (Organización Nacional de Cegos de España)Prevención da cegueiraDescrición de deficiencias visuais (Disc@pnet)Braillín, un boneco atractivo para calquera neno, con ou sen discapacidade, que permite familiarizarse co sistema de escritura e lectura brailleAxudas Técnicas36838ID00897494007150-90057129528256DOID:1432HP:0000618D001766C10.597.751.941.162C97109C0155020