intermittent connectivity issues in virtual server images

Hello,
I have a few virtual server images running for development purposes and
have been experiencing intermittent connectivity issues for quite a
while. First of all my configuration...
VPC image 1:
Windows Server 2003 Enterprise Edition SP1
Being used as domain controller and DNS server for all other images
VPC image 2:
Windows Server 2003 Enterprise Edition SP1
SQL Server Enterprise Edition 2000 SP3 (8.00.760)
VPC image 3:
Windows Server 2003 Enterprise Edition SP1
IIS 6.0
.NET Framework 1.0 (for ASP.NET stuff)
All these images are running on a Pentium M 1.75ghz with 2GB of RAM
(which seems to be enough horsepower to handle everything) and using
Microsoft Virtual PC 5.3.582.27 under Windows XP Pro SP2.
On to my problem...
Intermittently, an ASP.NET application I wrote would error out upon
trying to establish a connection to the SQL Server (using
System.Data.SQLClient). I return the error...
"System.Data.SqlClient.SqlException: SQL Server does not exist or
access denied"
...the stack trace doesn't provide much insight as to why. This error
will generally occur multiple times until an attempt succeeds and then
it appears to keep working as long as I don't leave the system idle too
long (i.e. twenty minutes or so).
This could of course be caused by numorous virtual networking problems
but we can eliminate all of that (I think) by this second issue.
Today I attempted to import some data via the DTS Import/Export Wizard
in Enterprise Manager, as soon as I attempt to click Next on the
"Choose a Data Source" dialog I receive...
Error Source: Microsoft OLE DB Provider for SQL Server
Error Description: [DBNETLIB][ConnectionOpen (Connect()).]SQL Server
does not exist or access denied.
Context: Error during initialization of the provider.
This is occuring while running EM on the Virtual Image containing SQL
Server. Someone with more knowledge of how SQL Server establishes
named pipes connections may be able to determine if this eliminates the
virtual network as a culpret or not (I'm not positive it does).
Anyway, ideas?
Thanks,
Ben.
PS I should add, while the errors are being thrown I am still able to
ping the sql virtual image from my iis virtual image. I also have
another ASP.NET app (MS CRM) that is able to communicate with the
server the whole time and I am able to establish a Query Analyzer
connection without fail (using both integrated and sql server
authentication). I'm about stumped.<ben.usenet.alias@.gmail.com> wrote in message
news:1146078164.773174.237320@.j33g2000cwa.googlegroups.com...
> Hello,
> I have a few virtual server images running for development purposes and
> have been experiencing intermittent connectivity issues for quite a
> while. First of all my configuration...
> VPC image 1:
> Windows Server 2003 Enterprise Edition SP1
> Being used as domain controller and DNS server for all other images
> VPC image 2:
> Windows Server 2003 Enterprise Edition SP1
> SQL Server Enterprise Edition 2000 SP3 (8.00.760)
> VPC image 3:
> Windows Server 2003 Enterprise Edition SP1
> IIS 6.0
> .NET Framework 1.0 (for ASP.NET stuff)
> All these images are running on a Pentium M 1.75ghz with 2GB of RAM
> (which seems to be enough horsepower to handle everything) and using
> Microsoft Virtual PC 5.3.582.27 under Windows XP Pro SP2.
> On to my problem...
> Intermittently, an ASP.NET application I wrote would error out upon
> trying to establish a connection to the SQL Server (using
> System.Data.SQLClient). I return the error...
> "System.Data.SqlClient.SqlException: SQL Server does not exist or
> access denied"
> ...the stack trace doesn't provide much insight as to why. This error
> will generally occur multiple times until an attempt succeeds and then
> it appears to keep working as long as I don't leave the system idle too
> long (i.e. twenty minutes or so).
> This could of course be caused by numorous virtual networking problems
> but we can eliminate all of that (I think) by this second issue.
> Today I attempted to import some data via the DTS Import/Export Wizard
> in Enterprise Manager, as soon as I attempt to click Next on the
> "Choose a Data Source" dialog I receive...
> Error Source: Microsoft OLE DB Provider for SQL Server
> Error Description: [DBNETLIB][ConnectionOpen (Connect()).]SQL Server
> does not exist or access denied.
> Context: Error during initialization of the provider.
> This is occuring while running EM on the Virtual Image containing SQL
> Server. Someone with more knowledge of how SQL Server establishes
> named pipes connections may be able to determine if this eliminates the
> virtual network as a culpret or not (I'm not positive it does).
>
What network are the VM's bound to? Your host OS's wireless network?
Here's what I do
1) Install the Loopback Adapter in the Host OS|||<ben.usenet.alias@.gmail.com> wrote in message
news:1146078164.773174.237320@.j33g2000cwa.googlegroups.com...
> Hello,
> I have a few virtual server images running for development purposes and
> have been experiencing intermittent connectivity issues for quite a
> while. First of all my configuration...
> VPC image 1:
> Windows Server 2003 Enterprise Edition SP1
> Being used as domain controller and DNS server for all other images
> VPC image 2:
> Windows Server 2003 Enterprise Edition SP1
> SQL Server Enterprise Edition 2000 SP3 (8.00.760)
> VPC image 3:
> Windows Server 2003 Enterprise Edition SP1
> IIS 6.0
> .NET Framework 1.0 (for ASP.NET stuff)
> All these images are running on a Pentium M 1.75ghz with 2GB of RAM
> (which seems to be enough horsepower to handle everything) and using
> Microsoft Virtual PC 5.3.582.27 under Windows XP Pro SP2.
> On to my problem...
> Intermittently, an ASP.NET application I wrote would error out upon
> trying to establish a connection to the SQL Server (using
> System.Data.SQLClient). I return the error...
> "System.Data.SqlClient.SqlException: SQL Server does not exist or
> access denied"
> ...the stack trace doesn't provide much insight as to why. This error
> will generally occur multiple times until an attempt succeeds and then
> it appears to keep working as long as I don't leave the system idle too
> long (i.e. twenty minutes or so).
> This could of course be caused by numorous virtual networking problems
> but we can eliminate all of that (I think) by this second issue.
> Today I attempted to import some data via the DTS Import/Export Wizard
> in Enterprise Manager, as soon as I attempt to click Next on the
> "Choose a Data Source" dialog I receive...
> Error Source: Microsoft OLE DB Provider for SQL Server
> Error Description: [DBNETLIB][ConnectionOpen (Connect()).]SQL Server
> does not exist or access denied.
> Context: Error during initialization of the provider.
> This is occuring while running EM on the Virtual Image containing SQL
> Server. Someone with more knowledge of how SQL Server establishes
> named pipes connections may be able to determine if this eliminates the
> virtual network as a culpret or not (I'm not positive it does).
> Anyway, ideas?
Oops.
Here's what I do to connect my VM's to each other and my host OS.
-Install the Looblack Adapter in the host OS
How to install the Microsoft Loopback adapter in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;839013
Assign a private IP address to the Loopback adapter. I use 10.240.0.1 mask
255.255.255.0
Then in Virtual Server add a Virtual Network for that adapter and enable the
virtual server DHCP server and let DHCP assign a range of the 10.240.0.X
network, reserving some address for VM's with fixed IP's.
David|||I like that idea. I've been toying around with the idea of isolating
my test environment further (putting it on it's own subnet) but I still
do need to connect my virtual servers to the internet for some items.
I'm considering adding a second virtual NIC on my virtual domain
controller. I'd run the internal against the loopback adapter (as you
described) and the second virtual NIC against my laptop's wired NIC.
Then I'd throw ISA on the virtual domain controller to route outside
traffic. Everything on the inside would exist on 10.x.x.x addys with a
255.255.255.0 netmask. The DNS on my virtual domain controller already
forwards unhandled requests to the corporate DNS here and that would
continue as is. The only downside I see to this is that I wouldn't be
able to hit my virtual server's web service from my laptop (I like to
point my laptop's browser at my virtual server running IIS to test
client functionality).
As to my original problem, I think I'm close to a solution (unrelated
to this conversation). I'll post more when I have something concrete
so that other's can benefit from it.
Ben.