HP Storage Mirroring Software - Manual (Page 527)

Connections Page 526 of 677
Data queues
During the Storage Mirroring Recover installation, you identified the amount of disk
space that can be used for Storage Mirroring Recover queuing. Queuing to disk allows
Storage Mirroring Recover to accommodate high volume processing that might
otherwise fill-up system memory. For example, on the source, this may occur if the data
is changing faster than it can be transmitted to the target, or on the target, a locked file
might cause processing to back up.
The following diagram will help you understand how queuing works. Each numbered
step is described after the diagram.
1. If data cannot immediately be transmitted to the target, it is stored, or queued, in
system memory. You can configure how much system memory you want to use for
queuing. By default, 128 or 512 MB of memory is used, depending on your
operating system.
2. When the allocated amount of system memory is full, new changed data bypasses
the full system memory and is queued directly to disk. Data queued to disk is
written to a transaction log. Each transaction log can store 5 MB worth of data.
Once the log file limit has been reached, a new transaction log is created. The logs
can be distinguished by the file name which includes the target IP address, the
Storage Mirroring Recover port, the connection ID, and an incrementing sequence
number.
Note: You may notice transaction log files that are not the defined size limit. This
is because data operations are not split. For example, if a transaction log