Ahoy there! This is my personal blog which I use as my memory extension and a medium to share stuff that could be useful to others.

Problem:

BlackBerry Exchange Server (BES) 5 users experience intermittent issues with their devices. For example, they receive some emails promptly whereas others after a delay of a few minutes.

The following "Warning" (Event 20709) is seen in the Application Event Logs on the BES 5 Server:

Application Event Log Warning

The following error is seen in the BlackBerry Messaging Agent (MAGT) logs:

[40720] (11/14 00:03:57.796):{0x19E4} MAPI call failed. Error ‘Network problems are preventing connection to the Microsoft Exchange Server computer.’, LowLevelError 6, Component ‘Microsoft Exchange Server Information Store’, Context 1300

Background & Analysis:

  • We were failing over our BES 5 server from primary (site A) to standby (site B).
  • In site A, the BES 5 server connected directly to 1 Exchange CAS node, whereas in site B, the BES 5 server connected to an F5 load balancer which load balanced connections across 2 Exchange CAS nodes (redundancy).
  • Our Exchange Server was on Exchange 2010.
  • BES 5 communicates with Exchange via MAPI/RPC.

 

Solution:

WORKAROUND: Configure BES 5 to communicate directly with an Exchange CAS node, bypassing the F5. Refer BlackBerry KB28704

Possible Solution: I haven’t tested this solution yet, but BlackBerry KB26490 describes a possible solution with a specific F5 configuration (iRules).

 NOTE: Using an F5 load balancer in front of Exchange CAS nodes requires an appropriate configuration of the F5. Refer this detailed F5 deployment guide.

(1) The solution above describes a successful problem-solving experience and may not be applicable to other problems with similar symptoms.

(2) Your rating of this post will be much appreciated as it gives me and others who read this article, an indication of whether this solution has worked for people other than me. Also, feel free to leave comments.

 

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Symptoms:

  • Very poor SAN performance on Cisco UCS B200 M3 Blades.
  • Deploying VMs from templates and cloning VMs hang.
  • CPU stats in a VM indicated 100% cpu in wio state

Background:

  • Cisco UCS provides a QoS feature to allow prioritization of certain types of traffic.
  • Cisco UCS supported multi-hop FCoE from release 2.1 onwards.

 

Resolution:

Enable Packet Drop (no pause) for any enabled priority (in my case below, it was Platinum) when using UCS 2.1+ i.e. UCS with multi-hop FCoE. This was not required in earlier versions of UCS using native FC.

QoS

Root Cause:

I am not a networking expert to provide much clarity here, but according to Jeremy Waldrop, packet drop cannot be enabled on 2 different QoS groups on the same interfaces. I thought this wouldn’t matter because the QoS groups are assigned to different CoS groups, but I don’t know much about this to discuss further.

 

(1) The solution above describes a successful problem-solving experience and may not be applicable to other problems with similar symptoms.

(2) Your rating of this post will be much appreciated as it gives me and others who read this article, an indication of whether this solution has worked for people other than me. Also, feel free to leave comments.

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Symptoms: The following errors were encountered when associating a Service Profile with a B200 M3 UCS Blade:

ERROR 1:

SRIOV PF/VF vNIC configuration failure. Incompatible Bios Policy Settings for SRIOV vNICs There are not enough resources overall.

ERROR 2:

[FSM:STAGE:REMOTE-ERROR]: Configure adapter for pre-boot environment(FSM-STAGE:sam:dme:ComputePhysicalAssociate:NicConfigPnuOSLocal)

 

toomanyvnics-1

Background: 

  • Cisco’s Virtual Interface Cards (VIC) such as the VIC 1240 support SRIOV and are used with Dynamic vNICS when provisioning Hypervisor hosts such as ESXi on Cisco UCS Blades.
  • Dynamic vNICs may be assigned using a “Global” Dynamic vNIC policy (applied to all adapters in the Blade) or to a specific adapter.
  • There is also a provision to associate a Dynamic vNIC policy with a vNIC Template.
  • Each CIsco VIC supports a maximum number of dynamic vNICS.

 

Resolution:

ERROR 1: The dynamic vNIC policy was disassociated from the vNIC template and assigned as a “global” dynamic vNIC policy.

ERROR 2: The number of vNICS in the global dynamic vNIC policy was reduced to 54 vNICS.

 

Root Cause:

ERROR 1: Caused by associating a dynamic vNIC policy (54 vNICS) with a vNIC template that was assigned to both vNICS associated with the Blade. It’s not about the number of vNICS in the policy (54) which caused the issue here, but the use of the policy in a vNIC template. As a vNIC template is meant for vNICS and can be assigned to each of the maximum number of vNICS permitted for the adapter, it does not make sense to assign a dynamic vNIC policy to a vNIC template. I don’t know why this option is provided in the vNIC template.

ERROR 2: Caused by associating a global dynamic vNIC policy (96 vNICS) with the Blade via the Service Profile. The number of vNICS exceeded the permissible maximum.

 

(1) The solution above describes a successful problem-solving experience and may not be applicable to other problems with similar symptoms.

(2) Your rating of this post will be much appreciated as it gives me and others who read this article, an indication of whether this solution has worked for people other than me. Also, feel free to leave comments.

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Given below are the port requirements for connectivity among the nodes of a WSFC (as per my experience with a WSFC comprising 4 nodes running Windows Server 2012 Standard). This connectivity is required for node join (during cluster creation) and normal cluster operations.

 

# PORT(S) PROTOCOL(S)
1. 3343 TCP and UDP
2. 135 TCP
3. 137 UDP
4. 49152-65535 UDP
5. N/A ICMP

 

NOTE:  The dynamic port range above may be customized, but I don’t know if it has to be as big as the default range.

Well, I was involved in building a multi-site (2 sites) WSFC using Windows Server 2012 Standard to host a SQL Server 2012 AlwaysOn Availability Group. After opening the required ports on the firewalls in both sites, we could not create a cluster. i.e. we could not join a node from the other site. When we opened all ports on our firewalls (just to test), the cluster could be created. When I raised a ticket with Microsoft and their technician pointed me to the same Microsoft KB Article which we referred to in the first place.

Our SysAdmins did not experience similar problems when creating Windows Server 2008 clusters, but those clusters were local to a site.

So, I enabled Windows Firewall Logging on the node on which I attempted to create a cluster and then tried to add a node from the remote site. From outbound connection logging, I observed that apart from the ports specified in the Microsoft KB article, the cluster creation was trying to “ping” the remote node. And ICMP was not allowed between our nodes across sites! When ICMP was enabled, our cluster was created.

I’m primarily from a *nix background and do not know if it is well known in the “Windows world” that ICMP is a requirement for WSFC. However,  Microsoft’s KB article on port requirements should have been comprehensive and mentioned ICMP.

UPDATE (07-AUG-2013): Microsoft Support just called me and acknowledged that this important information (ICMP required for WSFC) is missing from their public documentation and they would update the same KB article.

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For whatever reason, Microsoft stopped enabling the useful “Telnet Client” by default in its Operating Systems since Windows Server 2008 R2. So, on such OSes, the Telnet Client has to be enabled as a “Feature”.

After my first brush with Windows Server 2012, I realized that I must have shortcuts and commands handy to prevent the UI overhaul from impacting my efficiency.

So, here’s a handy command to install the Telnet client (run from the MS-DOS command prompt):

pkgmgr /iu:"TelnetClient"
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