TECHNICAL BULLETIN
                                Bulletin #1-265

Date:  March 23, 1990

                          Mirroring Large Disk Drives

Traditionally, NetWare 286 volume information tables have resided on sectors 16 and 17.  These sectors are automatically mirrored in NetWare 286.  As disk drives have increased in capacity, so have the volume information tables.  Disk drives larger than 600MB store the volume information tables on sectors 22 through 25, as well as on sectors 16 and 17.  However, sectors 22 through 25 are not remirrored through the REMIRROR command, or through auto-remirror.  Thus, if the primary disk fails, the volume information table on sectors 22 through 25 will be lost when the primary disk is replaced.  This will result in "Data Mirror Mismatch" errors when booting the file server.

To prevent these problems on disks larger than 600MB, Novell has placed an operating system patch on NetWire that provides disk mirroring for sectors 22 through 25.  The name of the patch file is 215MIR.ZIP.  Use PKUNZIP.EXE to extract all the files from 215MIR.ZIP.  The READ.ME file included in 215MIR.ZIP contains proper documentation for executing the patch.  Read the instructions carefully before proceeding.