FileUtilDoc.tioga
Bob Hagmann May 15, 1986 7:41:41 am PDT
FileUtil
CEDAR 6.1 — FOR INTERNAL XEROX USE ONLY
FileUtil
Bob Hagmann
© Copyright 1985 Xerox Corporation. All rights reserved.
Abstract: This package does some File system maintence. All these commands will be of interest to experts only. You can compute and print the VAM from the file headers, force the VAM to match the file headers, or scan the disk looking for pages that are not in any file. The VAM is the ``Volume Allocation Map'' and is a hint where free pages are on disk. If the disk headers and the VAM become out of sync, performance will suffer.
Created by: Bob Hagmann
Maintained by: Hagmann.pa
Keywords: File Package Utilities, VAM
XEROX Xerox Corporation
Palo Alto Research Center
3333 Coyote Hill Road
Palo Alto, California 94304
For Internal Xerox Use Only
1. Introduction
This package does some File system maintence. You can compute and print the VAM from the file headers, force the VAM to match the file headers, or scan the disk looking for pages that are not in any file. The VAM is the ``Volume Allocation Map'' and is a hint where free pages are on disk. If the disk headers and the VAM become out of sync, performance will suffer.
All of these commands have matching "Stop" commands. Do not use the "STOP!" button — the multi-processing going on to do some of the enumeration may not recover completely or gracefully.
2. Commands
VAMStats volumeName
Compute and show some accuracy statistics on the VAM for the given volume
StopVAMStats
Stop VAMStats early
ComputeVAM volumeName
Compute VAM from disk labels for the given volume
StopComputeVAM
Stop Compute VAM from disk labels
DeleteOrphanPages volumeName
Mark pages as free that are not in any file, or are not in the file they claim to be in. This is a long running command (5 minutes on a 75,000 page logical volume). This should be normally done after a boot or rollback, with little other activity on the disk.
StopDeleteOrphanPages
Stop Delete Orphan Pages