Hi, I am trying to confure FreeSwitch for my VOIP gateway. It works really good in testing in low load. However, whenever i try to increase load it takes only around 240 concurrent calls and any call beyond that it starts giving 503, Bad Gateway errors. On console i start getting below error, which led me to believe that database issue and it seems it cannot take more connections. I tried setting up MySQL as database as well with same results. 2014-10-13 20:00:50.680811 [ERR] switch_core_sqldb.c:1196 SQL ERR: [select state,status,rpid,presence_id,uuid from sip_dialogs where uuid != '35579a26-4bc4-40ab-ae5c-a2b6f460c801' and call_info_state != 'seized' and hostname='BOX02' and profile_name='internal' and ((sip_from_user='sipp' and sip_from_host='10.0.0.14') or presence_id='sipp@10.0.0.14') order by rcd desc] unable to open database file 2014-10-13 20:00:50.680811 [ERR] switch_core_sqldb.c:586 NATIVE SQL ERR [unable to open database file] update sip_subscriptions set version=version+1 where hostname='BOX02' and profile_name='internal' and sip_subscriptions.event != 'line-seize' and sip_subscriptions.proto='sip' and (event='presence' or event='dialog') and sub_to_user='sipp' and (sub_to_host='10.0.0.14' or sub_to_host='10.0.0.15' or sub_to_host='N/A' or presence_hosts like '%10.0.0.14%') and (sip_subscriptions.profile_name = 'internal' or presence_hosts like '%10.0.0.14%') 2014-10-13 20:00:50.680811 [ERR] switch_core_sqldb.c:1196 SQL ERR: [select distinct sip_subscriptions.proto,sip_subscriptions.sip_user,sip_subscriptions.sip_host,sip_subscriptions.sub_to_user,sip_subscriptions.sub_to_host,sip_subscriptions.event,sip_subscriptions.contact,sip_subscriptions.call_id,sip_subscriptions.full_from,sip_subscriptions.full_via,sip_subscriptions.expires,sip_subscriptions.user_agent,sip_subscriptions.accept,sip_subscriptions.profile_name,'CS_ROUTING','unknown','10.0.0.14',sip_presence.status,sip_presence.rpid,sip_presence.open_closed,'','',sip_subscriptions.version, '',sip_subscriptions.orig_proto,sip_subscriptions.full_to,sip_subscriptions.network_ip, sip_subscriptions.network_port from sip_subscriptions left join sip_presence on (sip_subscriptions.sub_to_user=sip_presence.sip_user and sip_subscriptions.sub_to_host=sip_presence.sip_host and sip_subscriptions.profile_name=sip_presence.profile_name and sip_subscriptions.hostname=sip_presence.hostname) where sip_subscriptions.hostname='BOX02' and sip_subscriptions.profile_name='internal' and sip_subscriptions.event != 'line-seize' and sip_subscriptions.proto='sip' and (event='presence' or event='dialog') and sub_to_user='sipp' and (sub_to_host='10.0.0.14' or sub_to_host='10.0.0.15' or sub_to_host='N/A' or presence_hosts like '%10.0.0.14%') ] unable to open database file Please help. Thanks, Vishal