2-152 Sun StorEdge 5310 NAS Troubleshooting Guide • December 2004
9. Enter the desired size of the Mirror Buffer.
The mirror buffer stores file system write transactions while they are being
transferred to the mirror server. The size of the mirror buffer depends on a variety of
factors, but must be at least 100 MB. You may want to create a mirror buffer that is
approximately 10% of the size of the file volume you are replicating. The size you
choose should depend on how much information is being written to the file volume
rather than the size of the file volume. The file volume free space on the active server
will be reduced by the allocation size of the mirror buffer. Our general
recommendation is 10% of the volume to be replicating.
10. Select option "7", "Sav e Changes" to proceed.
11. To verify status, return to the Mirrors submenu, and view details by selecting the
"Mirror" option, usually "A" or "B."
This display shows status complete and details of current operations.
2.37 StorEdge File Replicator Issues
Since File Replicator operates at the disk block level, the mirror system is an exact
replica of the master system. However, since replicating operations are not strictly
real time, the mirror system may lag the master by a time delta dependent on the
speed and quality of the network. While this network lag may prevent the mirror
system from being an exact copy of the master at any given point, the integrity of the
mirror system is guaranteed at all times. Only complete file system transactions are
replicating. In the course of creating a duplicate volume, a mirror goes through three
main phases: creation, replication, or sync, and sequencing. File Replicator is a fault-
tolerant technology. In all of the three main phases, the mirror handles errors with
the intent of self-recovery as much as possible. When errors are encountered that are
too severe for the mirror to handle on its own, it enters an ERROR state. In this
state, user intervention is required to remedy the error and restart the mirror.
A list of all mirror states and their definitions can be found in the "Error Codes"
section at the end of this document. The mirror states are very useful for
troubleshooting.

Configuration

File Replicator requires that the NIC card to be used for File Replicator is designate
as a mirror role, and that the network connection for this card be private. Also check
that a host entry exists in both systems to provide a path to mirror and master.