=head1 NAME

dasalvager - Initializes the Salvager component of the dafs process

=head1 SYNOPSIS

=for html
<div class="synopsis">

B<dasalvager>
    [I<initcmd>] S<<< [B<-partition> <I<name of partition to salvage>>] >>>
    S<<< [B<-volumeid> <I<volume id to salvage>>] >>> [B<-debug>] [B<-nowrite>]
    [B<-inodes>] [B<-force>] [B<-oktozap>] [B<-rootinodes>]
    [B<-salvagedirs>] [B<-blockreads>]
    S<<< [B<-parallel> <I<# of max parallel partition salvaging>>] >>>
    S<<< [B<-tmpdir> <I<name of dir to place tmp files>>] >>>
    [B<-showlog>] [B<-showsuid>] [B<-showmounts>]
    S<<< [B<-orphans> (ignore | remove | attach)] >>> [B<-help>]

=for html
</div>

=head1 DESCRIPTION

The B<dasalvager> command initializes the Salvager component of the C<dafs>
process. In the conventional configuration, its binary file is located in
the F</usr/afs/bin> directory on a file server machine.

The Salvager restores internal consistency to corrupted read/write volumes
on the local file server machine where possible. For read-only or backup
volumes, it inspects only the volume header:

=over 4

=item *

If the volume header is corrupted, the Salvager removes the volume
completely and records the removal in its log file,
F</usr/afs/logs/SalvageLog>. Issue the B<vos release> or B<vos backup>
command to create the read-only or backup volume again.

=item *

If the volume header is intact, the Salvager skips the volume (does not
check for corruption in the contents). However, if the File Server notices
corruption as it initializes, it sometimes refuses to attach the volume or
bring it online. In this case, it is simplest to remove the volume by
issuing the B<vos remove> or B<vos zap> command. Then issue the B<vos
release> or B<vos backup> command to create it again.

=back

Unlike other server process initialization commands, the Salvager
command is designed to be issued at the command shell prompt, as well as
being placed into a file server machine's F</usr/afs/local/BosConfig> file
with the B<bos create> command. It is also possible to invoke the Salvager
remotely by issuing the B<bos salvage> command.

Combine the command's options as indicated to salvage different numbers of
read/write volumes:

=over 4

=item *

To salvage all volumes on the file server machine, provide no arguments.
No volumes on the machine are accessible to Cache Managers during the
salvage, because the BOS Server stops the File Server and Volume Server
processes while the Salvager runs.

=item *

To salvage all of the volumes on one partition, provide the B<-partition>
argument. As for a salvage of all volumes on the machine, no volumes on
the machine are accessible to Cache Managers during the salvage operation.

=item *

To salvage only one volume, combine the B<-partition> and B<-volumeid>
arguments. Only that volume is inaccessible to Cache Managers, because the
BOS Server does not shutdown the File Server and Volume Server processes.

=back

The Salvager normally salvages only those read/write volumes that are
marked as having been active when a crash occurred. To have it salvage all
relevant read/write volumes, add the B<-force> flag.

The Salvager normally creates new inodes as it repairs damage. If the
partition is so full that there is no room for new inodes, use the
B<-nowrite> argument to bringing undamaged volumes online without
attempting to salvage damaged volumes. Then use the B<vos move> command to
move one or more of the undamaged volumes to other partitions, freeing up
the space that the Salvager needs to create new inodes.

By default, multiple Salvager subprocesses run in parallel: one for each
partition up to four, and four subprocesses for four or more
partitions. To increase or decrease the number of subprocesses running in
parallel, provide a positive integer value for the B<-parallel> argument.

If there is more than one server partition on a physical disk, the
Salvager by default salvages them serially to avoid the inefficiency of
constantly moving the disk head from one partition to another. However,
this strategy is often not ideal if the partitions are configured as
logical volumes that span multiple disks. To force the Salvager to salvage
logical volumes in parallel as if they were on separate disks, provide the
string C<all> as the value for the B<-parallel> argument.

To set both parameters at the same time, append the number of Salvager
processes to the string C<all>. For example, C<-parallel all5> treats
each partition as a separate disk and runs five Salvager processes, thus
salvaging five partitions at a time.

The Salvager creates temporary files as it runs, by default writing them
to the partition it is salvaging. The number of files can be quite large,
and if the partition is too full to accommodate them, the Salvager
terminates without completing the salvage operation (it always removes the
temporary files before exiting). Other Salvager subprocesses running at
the same time continue until they finish salvaging all other partitions
where there is enough disk space for temporary files. To complete the
interrupted salvage, reissue the command against the appropriate
partitions, adding the B<-tmpdir> argument to redirect the temporary files
to a local disk directory that has enough space.

The B<-orphans> argument controls how the Salvager handles orphaned files
and directories that it finds on server partitions it is salvaging. An
I<orphaned> element is completely inaccessible because it is not
referenced by the vnode of any directory that can act as its parent (is
higher in the filespace). Orphaned objects occupy space on the server
partition, but do not count against the volume's quota.

To generate a list of all mount points that reside in one or more volumes,
rather than actually salvaging them, include the B<-showmounts> flag.

This command does not use the syntax conventions of the AFS command
suites. Provide the command name and all option names in full.


=head1 OPTIONS

=over 4

=item [I<initcmd>]

Accommodates the command's use of the AFS command parser, and is optional.

=item B<-partition> <I<name of partition to salvage>>

Specifies the name of the partition to salvage. Specify the full partition
name using the form F</vicepI<x>> or F</vicepI<xx>>. Omit this argument to
salvage every partition on the file server machine.

=item B<-volumeid> <I<volume id to salvage>>

Specifies the volume ID of a specific read/write volume to salvage.  The
B<-partition> argument must be provided along with this one and specify
the volume's actual site.

=item B<-debug>

Allows only one Salvager subprocess to run at a time, regardless of the
setting of the B<-parallel> option. Include it when running the Salvager
in a debugger to make the trace easier to interpret.

=item B<-nowrite>

Brings all undamaged volumes online without attempting to salvage any
damaged volumes.

=item B<-inodes>

Records in the F</usr/afs/logs/SalvageLog> file a list of all AFS inodes
that the Salvager modified.

=item B<-force>

Inspects all volumes for corruption, not just those that are marked as
having been active when a crash occurred.

=item B<-oktozap>

Removes a volume that is so damaged that even issuing the B<vos zap>
command with the B<-force> flag is ineffective. Combine it with the
B<-partition> and B<-volumeid> arguments to identify the volume to remove.
Using this flag will destroy data that cannot be read, so use only with
caution and when you're certain that nothing in that volume is still
needed.

=item B<-rootinodes>

Records in the F</usr/afs/logs/SalvageLog> file a list of all AFS inodes
owned by the local superuser C<root>.

=item B<-salvagedirs>

Salvages entire directory structures, even if they do not appear to be
damaged. By default, the Salvager salvages a directory only if it is
flagged as corrupted.

=item B<-blockreads>

Forces the Salvager to read a partition one disk block (512 bytes) at a
time and to skip any blocks that are too badly damaged to be salvaged.
This allows it to salvage as many volumes as possible. By default, the
Salvager reads large disk blocks, which can cause it to exit prematurely
if it encounters disk errors. Use this flag if the partition to be
salvaged has disk errors.

=item B<-parallel> <I<# of max parallel partition salvaging>>

Specifies the maximum number of Salvager subprocesses to run in parallel.
Provide one of three values:

=over 4

=item *

An integer from the range C<1> to C<32>. A value of C<1> means that a
single Salvager process salvages the partitions sequentially.

=item *

The string C<all> to run up to four Salvager subprocesses in parallel on
partitions formatted as logical volumes that span multiple physical
disks. Use this value only with such logical volumes.

=item *

The string C<all> followed immediately (with no intervening space) by an
integer from the range C<1> to C<32>, to run the specified number of
Salvager subprocesses in parallel on partitions formatted as logical
volumes. Use this value only with such logical volumes.

=back

The BOS Server never starts more Salvager subprocesses than there are
partitions, and always starts only one process to salvage a single
volume. If this argument is omitted, up to four Salvager subprocesses run
in parallel but partitions on the same device are salvaged serially.

=item B<-tmpdir> <I<name of dir to place tmp files>>

Names a local disk directory in which the Salvager places the temporary
files it creates during a salvage operation, instead of writing them to
the partition being salvaged (the default). If the Salvager cannot write
to the specified directory, it attempts to write to the partition being
salvaged.

=item B<-showlog>

Displays on the standard output stream all log data that is being written
to the F</usr/afs/logs/SalvageLog> file.

=item B<-showsuid>

Displays a list of the pathnames for all files that have the setuid or
setgid mode bit set.

=item B<-showmounts>

Records in the F</usr/afs/logs/SalvageLog> file all mount points found in
each volume. The Salvager does not repair corruption in the volumes, if
any exists.

=item B<-orphans> (ignore | remove | attach)

Controls how the Salvager handles orphaned files and directories.  Choose
one of the following three values:

=over 4

=item ignore

Leaves the orphaned objects on the disk, but prints a message to the
F</usr/afs/logs/SalvageLog> file reporting how many orphans were found and
the approximate number of kilobytes they are consuming. This is the
default if the B<-orphans> argument is omitted.

=item remove

Removes the orphaned objects, and prints a message to the
F</usr/afs/logs/SalvageLog> file reporting how many orphans were removed
and the approximate number of kilobytes they were consuming.

=item attach

Attaches the orphaned objects by creating a reference to them in the vnode
of the volume's root directory. Since each object's actual name is now
lost, the Salvager assigns each one a name of the following form:

=over 4

=item C<__ORPHANFILE__.I<index>> for files.

=item C<__ORPHANDIR__.I<index>> for directories.

=back

where I<index> is a two-digit number that uniquely identifies each
object. The orphans are charged against the volume's quota and appear in
the output of the B<ls> command issued against the volume's root
directory.

=back

=item B<-help>

Prints the online help for this command. All other valid options are
ignored.

=back

=head1 EXAMPLES

The following command instructs the Salvager to attempt to salvage the
volume with volume ID 258347486 on F</vicepg> on the local machine.

   % /usr/afs/bin/dasalvager -partition /vicepg -volumeid 258347486

=head1 PRIVILEGE REQUIRED

To issue the command at the shell prompt, the issuer must be logged in as
the local superuser C<root>.

=head1 SEE ALSO

L<BosConfig(5)>,
L<SalvageLog(5)>,
L<bos_create(8)>,
L<bos_getlog(8)>,
L<bos_salvage(8)>,
L<vos_move(1)>

=head1 COPYRIGHT

IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

This documentation is covered by the IBM Public License Version 1.0.  It was
converted from HTML to POD by software written by Chas Williams and Russ
Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.

