Specifications

VMware, Inc. 191
Chapter 13 Troubleshooting
Active Server (Unsafe) Queue
vCenter Server Heartbeat considers the active server queue as unsafe because the data in this queue has not
yet been replicated across the VMware Channel to the passive server and therefore could be lost in the event
of a failover. As a result of failover, some data loss is inevitable, with the exact amount depending on the
relationship between available VMware Channel bandwidth and the required data transmission rate. If the
required data transmission rate exceeds available VMware Channel bandwidth, the active server queue fills.
If the available VMware Channel bandwidth exceeds the required data transmission rate, the active server
queue empties. This situation is most commonly seen in a WAN environment, where VMware Channel
bandwidth is restricted. In a LAN that normally has high bandwidth on a dedicated channel, the size of the
active server queue is zero or near zero most of the time. On a server not protected with vCenter Server
Heartbeat, all data is technically unsafe and subject to loss if the server fails.
Passive Server (Safe) Queue
The passive server queue is considered safe because the data in this queue already was transmitted across the
VMware Channel from the active server, and is not lost in the event of a failover, which applies all updates to
the passive server as part of the process.
Both active and passive server queues are stored on disk by default in the <VMware vCenter Server
Heartbeat Install Directory>\R2\log directory, with a quota configured for the maximum permitted
queue size (by default, 1GB on each server). You can configure both the queue location and the quota.
Two methods to set the queue size:
 Start vCenter Server Heartbeat, open the vCenter Server Heartbeat Console, and select Advanced >
Communication > Configuration. Set the Max Disk Usage value and click Apply. Shut down and restart
vCenter Server Heartbeat for the change to take effect. You are not required to stop protected applications.
 Open the Server Configuration wizard and click the Logs tab. Set the Maximum Disk Usage value and
click Finish.
MaxDiskUsage Error Messages
The following error messages display when available disk space on the servers is exceeded.
[L9]Exceeded the Maximum Disk Usage
(VCChannelExceededMaxDiskUsageException)
This message indicates that you have exceeded the amount of allocated disk space reserved for the queue.
Symptom
vCenter Server Heartbeat exceeds its preconfigured queue size.
Causes
On the active server, the size of the active server queue has exceeded the disk quota allocated for it. On the
passive server, the size of the passive server queue has exceeded the disk quota allocated for it.
Resolution
While neither condition is critical, determine the sequence of events that led to the condition.
[L9]Exceeded the Maximum Disk Usage on the ACTIVE Server
This message indicates that you have exceeded the amount of allocated disk space reserved for the active
server (unsafe) queue.
NOTE vCenter Server Heartbeat is a symmetrical system and can operate with either server in the active role.
For this reason, the queue size is always set to the same value for both servers.