Volume Defragment Error Handling
This document applies to Volume Defragment for NetWare, version 1.28 and
Volume Defragment for NetWare is designed to detect and in some cases support
NetWare volumes that have problems. Some types of problems will prevent
defragmentation of volumes from starting.
There are several problems that a NetWare volume can have:
- Configuration Errors.
- Structural Errors.
- Hardware Errors.
Configuration errors are problems with missing volume segments, segments that
are not properly configured, missing mirror partitions, etc.
Before a volume defragment begins, the configuration of the volume and its
NetWare partitions are verified for correct configuration. If any problems are
found during this analysis, the volume will not be defragmented.
For Mirrored Partitions, all mirrors must be present and be 100% mirrored.
Structural errors are problems with the volume data structures such as FAT
Tables, Directory Tables, etc.
A very comprehensive "Volume Check" is performed on a volume before
a defragment begins. If any problems are found, the volume will not be
Structural errors are not corrected by the software. If errors are found, run
VREPAIR to correct the errors.
Hardware errors include Media Errors, Corrected Media Errors and other
hardware problems with the disk drive and controllers.
Most hardware problems are detected during the configuration tests. Media
errors are detected during a volume defragment.
Media errors during a volume defragment will not cause a volume defragment to
fail. If a Media Error happens during the read of a volume block, the data will
not be moved. If a Media Error happens during the write of a volume block, the
data will not be moved.
An exception to the above rule: If a volume is mirrored, and a read error
occurs, a read attempt will be made to one of the other mirrors. If the read
succeeds, the volume block will be moved and the old location will be marked
Logging of errors:
There is a command line option "-logfile=filename" that creates a
file on either a NetWare volume or DOS partition. Errors, warnings and status
information will be written to the file during a volume defragment.
During a defragment, the status screen displays the total number of volume
blocks that could not be moved due to sector read / write errors in the field:
"Blocks Not Moved". For normal healthy volumes, this field will be
zero at the end of a volume defragment. If this field is greater than zero, then
the volume has defective data areas that have not been corrected by NetWare's
Volume with defective data areas will often report errors on the console
during normal server operation (not during a volume defragment):
4-20-2001 9:26:56 am: FILESYS-5.10-178 [nmID=60017]
Error reading file NWDIR.JAR.
Offset 000315AEh data stream 0.
Read was requested by user ADMIN on station 6.
File path SYS:JAVA\BEANS\NWDIR.JAR.
This error message means that a user attempted to read data from this file.
The disk read returned "Media Error" and the read could not be
completed. For some reason NetWare does not Hotfix this data block. We recommend
backing up this volume, replacing the disk drive and then doing a volume
Read more about this error in our Novell NetWare File System Errors
document or our May
NetWare Hotfix sectors:
Volume Defragment for NetWare supports NetWare Hotfix sectors. This support
was added to version 1.28. Previous version prevented defragmentation of volumes
with Hotfix sectors.
Disk read errors during volume defragment.
If a sector read error occurs during a block move, and the volume is not
mirrored, the block is not moved and is left in its current location.
If the volume is mirrored, the read will be attempted on the other mirror
drives. If the read succeeds, the block move will complete.
Disk write errors during volume defragment.
If a sector write error occurs during a block relocation, the block is not
moved. Sector writes only occur when writing a volume block to a free location
on the volume. Internally the software keeps track of this bad location and does
not use this volume block for any further block moves.
Volume Defragment for NetWare handles disk errors very gracefully. For most
error types the solution is to not defragment the current file. A defragment
involves moving data blocks from used locations to free locations - an error
just means abort the current block move.