Posts

Client-specific message size limits - or the reason why iOS won't sent emails

Last week, a customer complained that he could not send emails with pictures with the native iOS email app. He attached three, four or five pictures to an emails, pushed the send button and instantly an error was displayed.

We checked the different connectors as well as the organizational limit for messages. The test mails were between 10 to 20 MB, and the message size limit was much higher.

The cross-check with Outlook Web Access indicated, that the issue was not a configured limit on one of the Exchange connectors. Instead, a quick search directed us towards the client-specific message size limits. Especially this statement caught our attention:

Veeam Backup & Replication: Backup of Microsoft Active Directory Domain Controller VMs

To backup a virtual machine, Veeam Backup & Replication needs two permissions:

  • permission to access and backup the VM, as well as the
  • permission to do specific tasks inside the VM

to guarantee a consistent backup. The former persmission is granted by the user account that is used to access the VMware vCenter server (sorry for the VMW focust at this point). Usually, this account has the Administrator role granted at the vCenter Server level. The latter permission is granted by a user account that has permissions inside the guest operating system.

Veeam and StoreOnce: Wrong FC-HBA driver/ firmware causes Windows BSoD

One of my customers bought a very nice new backup solution, which consists of a

  • HPE StoreOnce 5100 with ~ 144 TB usable capacity,
  • and a new HPE ProLiant DL380 Gen10 with Windows Server 2016

as new backup server. StoreOnce and backup server will be connected with 8 Gb Fibre-Channel and 10 GbE to the existing network and SAN. Veeam Backup & Replication 9.5 U3a is already in use, as well as VMware vSphere 6.5 Enterprise Plus. The backend storage is a HPE 3PAR 8200.

Database Availability Group (DAG) witness is in a failed state

As part of a maintenance job I had to update a 2-node Exchange Database Availability Group and a file-share witness server.

After the installation of Windows updates on the witness server and the obligatory reboot, the witness left in a failed state.

[PS] C:\Windows\system32>Get-DatabaseAvailabilityGroup -Identity DAG1 -Status | fl *wit*
WARNING: Database availability group ‘DAG01’ witness is in a failed state. The database
availability group requires the witness server to maintain quorum. Please use the
Set-DatabaseAvailabilityGroup cmdlet to re-create the witness server and the directory.

WitnessServer : fsw.domain.local
WitnessDirectory : C:\DAGFileShareWitnesses\DAG1.domain.local
AlternateWitnessServer :
AlternateWitnessDirectory :
WitnessShareInUse : InvalidConfiguration
DxStoreWitnessServers :

In my opinion, the re-creation of the witness server and the witness directory cannot be the correct way to solve this. There must be another way to solve this. In addition to this: The server was not dead. Only a reboot occured.

Out-of-Office replies are dropped due to empty MAIL FROM

Today I had an interesting support call. A customer noticed that Out-of-Office replies were not received by recipients, even though the OoO option were enabled for internal and external recipients. Internal recipients got the OoO reply, but none of the external recipients.

The Message Tracking Log is a good point to start. I quickly discovered that the Exchange server was unable to send the OoO mails. You can use the eventid FAIL to get a list of all failed messages.

Vembu BDR Suite v4.0 is now generally available

Vembu Technologies was founded in 2002, and with 60.000 customers and more than 4000 partners, Vembu is a leading provider with a comprehensive portfolio of software products and cloud services to small and medium businesses.

Last week, Vembu has announced the availability of Vembu BDR Suite v4.0! Vembu’s new release is all about maintaining business continuity and ensuring high availability. Apart from new features, this release features significant enhancements and bug fixes that are geared towards performance improvement.

Exam prep & experience: Citrix NetScaler Advanced Topics: Security, Management, and Optimization (1Y0-340)

In May 2018, Citrix released their new Citrix Certified Expert - Networking certification, which completet the networking certification path at the upper end (blog post on training.citrix.com). The track starts with the Associate (CCA-N), the lower-level certification is a requirement for achieving the higher-level certification, continues with the Professional (CCP-N), and ends with the Expert (CCE-N) certification. This is pretty cool, and I’m very happy that Citrix now offers the CCE-N, because the expert-level certification was missing all the time.

Vembu VMBackup Deployment Scenarios

Vembu was founded in 2002 and has over 60,000 customers worldwide. One of their core products is the Vembu BDR Suite, which is an one stop solution to all your Backup and DR needs. I wrote a longer blog post about the Vembu BDR Suite.

One part of this suite is Vembu VMBackup, which is a data protection solution that is designed to backup VMware and Microsoft Hyper-V virtual machines secure and simple way. The offered features are compareable to Veeam Backup & Replication.

"Cannot execute upgrade script on host" during ESXi 6.5 upgrade

I was onsite at one of my customers to update a small VMware vSphere 6.0 U3 environment to 6.5 U2c. The environment consists of three hosts. Two hosts in a cluster, and a third host is only used to run a HPE StoreVirtual Failover Manager.

The update of the first host, using the Update Manager and a HPE custom ESX 6.5 image, was pretty flawless. But the update of the second host failed with “Cannot execute upgrade script on host”

High CPU usage on Citrix ADC VPX

While building a small Citrix NetScaler… ehm… ADC VPX (I really hate this name…) lab environment, I noticed that the fan of my Lenovo T480s was spinning up. I was wondering why, because the VPX VM was just running for a couple of minutes - without any load. But the task manager told me, that the VMware Workstation Process was consuming 25% (I have a Intel i5 Quad Core CPU) CPU. So VMware Workstation was just eating a whole CPU core without doing anything. I would not care, but the fan… And it reminded me, that I’ve seen an similar behaviour in various VPX deployments on VMWare ESXi.