Virtual user custom properties missing on CD server

Question

We have 2 load balanced CD servers. Session affinity is disabled on the load balancer and we are using MongoDB for session storage.

User authentication is performed on a separate site. They are redirected back to our servers and logged into Sitecore as a virtual user. Custom properties are set on the user profile such as first and last name.

Once signed in, the user is presented with a welcome message ie. "Hello Bob". The value Bob will only display on one server. If the user is bounced to the second server by refreshing it, will just display "Hello", without the custom property.

I have verified that the data is getting saved to the ClientData table in core with the correct session Id.

I am at a loss on, what to look at now to get this to work. Any suggestions?

Session state from web.config:

<sessionState mode="Custom" customProvider="mongo" cookieless="false" timeout="20">
<providers>
    <add name="mongo"
         type="Sitecore.SessionProvider.MongoDB.MongoSessionStateProvider, 
     Sitecore.SessionProvider.MongoDB"
         connectionStringName="privateSession"
         pollingInterval="2"
         compression="true"
         sessionType="private"/>
</providers>

Shared session state:

<sharedSessionState patch:source="Sitecore.Analytics.Tracking.config" defaultProvider="mongo">
<providers>
    <clear />
    <add name="InProc" type="System.Web.SessionState.InProcSessionStateStore" />
    <add name="mongo" type="Sitecore.SessionProvider.MongoDB.MongoSessionStateProvider, Sitecore.SessionProvider.MongoDB" connectionStringName="sharedSession" pollingInterval="2" compression="true" sessionType="shared" patch:source="SharedSession.config" />
</providers>
<manager type="Sitecore.Analytics.Tracking.SharedSessionState.SharedSessionStateManager, Sitecore.Analytics">
    <param ref="tracking/sharedSessionState/config" desc="configuration" />
</manager>
<config type="Sitecore.Analytics.Tracking.SharedSessionState.SharedSessionStateConfig, Sitecore.Analytics">
    <param desc="maxLockAge">5000</param>
    <param desc="timeoutBetweenLockAttempts">10</param>
</config>
</sharedSessionState>

Answer 1

Virtual user information is saved in Session. By default Sitecore configuration doesn't share sessions information between few CD servers. That is why one CD server doesn't know anything about logged in users on others CD servers. You have few options, how to solve it:

1. Configure your hosting environment to use sticky load balancer. Link that was mentioned by Tamas is useful. Sticky load balancer means that user always will be routed to same CD. Other CDs will not know anything about this session on one CD, but it doesn't matter.
2. Use SessionState configuration that allows to share information between few servers. For Sitecore 8 it could be SQL Session State Provider. For Sitecore 7 you have a lot of options, you can use any ASPNet session state providers. It could be Redis, Couchbase, RavenDB, MongoDB, etc. This approach means that virtual user information will be saved in shared place and could be user by different CD servers.

P.S. Don't forget to use user.Profile.Save(); in your code.