=head1 NAME

bos salvage - Restores internal consistency to a file system or volume

=head1 SYNOPSIS

bos salvage B<-server> I<machine name>  [B<-partition> I<salvage partition>]
[B<-volume> I<salvage volume number or volume name>]
[B<-file> I<salvage log output file>]  [B<-all>]  [B<-showlog>]
[B<-parallel> I<# of max parallel partition salvaging>]
[B<-tmpdir> I<directory to place tmp files>]
[B<-orphans> I<ignore | remove | attach>]
[B<-cell> I<cell name>]
[B<-noauth>]  [B<-localauth>]  [B<-help>]

bos sa B<-se> I<machine name>  [B<-part> I<salvage partition>]
[B<-v> I<salvage volume number or volume name>]
[B<-f> I<salvage log output file>]  [B<-a>]  [B<-sh>]
[B<-para> I<# of max parallel partition salvaging>]
[B<-t> I<directory to place tmp files>]
[B<-o> I<ignore | remove | attach>]
[B<-c> I<cell name>]  [B<-n>]  [B<-l>]  [B<-h>]

=head1 DESCRIPTION

The C<bos salvage> command salvages (restores internal consistency to)
one or more volumes on the file server machine named by the B<-server>
argument. When processing one or more partitions, the command restores
consistency to corrupted read/write volumes where possible. For
read-only or backup volumes, it inspects only the volume header:

=over

=item *

If the volume header is corrupted, the Salvager removes the volume
completely and records the removal in its log file,
B</usr/afs/logs/SalvageLog>. Issue the C<vos release> or C<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 C<vos remove> or C<vos
zap> command. Then issue the C<vos release> or C<vos backup> command to
create it again.

=back

Use the indicated arguments to salvage a specific number of volumes:

=over

=item *

To process all volumes on a file server machine, provide the
B<-server> argument and the B<-all> flag. No volumes on the machine are
accessible to Cache Managers during the salvage operation, because
the BOS Server stops the File Server and Volume Server processes
while the Salvager runs. The BOS Server automatically restarts
them when the operation completes.

=item *

To process all volumes on one partition, provide the B<-server> and
B<-partition> arguments. As for a salvage of the entire machine, no
volumes on the machine are accessible to Cache Managers during the
salvage operation. The BOS Server automatically restarts the File
Server and Volume Server when the operation completes.

=item *

To salvage only one read/write volume, combine the B<-server>,
B<-partition>, and B<-volume> arguments. Only that volume is
inaccessible to Cache Managers, because the BOS Server does not
shutdown the File Server and Volume Server processes during the
salvage of a single volume. Do not name a read-only or backup
volume with the B<-volume> argument. Instead, remove the volume,
using the C<vos remove> or C<vos zap> command. Then create a new copy of
the volume with the C<vos release> or C<vos backup> command.

=back

During the salvage of an entire machine or partition, the C<bos status>
command reports the fs process's auxiliary status as C<Salvaging file
system>.

The Salvager always writes a trace to the B</usr/afs/logs/SalvageLog>
file on the file server machine where it runs. To record the trace in
another file as well (either in AFS or on the local disk of the
machine where the C<bos salvage> command is issued), name the file with
the B<-file> argument. To display the trace on the standard output stream
as it is written to the B</usr/afs/logs/SalvageLog> file, include the
B<-showlog> flag.

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, provide the string
all as the value for the B<-parallel> argument. Provide a positive
integer to specify the number of subprocesses to run in parallel (for
example, B<-parallel 5all> for five subprocesses), or omit the integer to
run up to four subprocesses, depending on the number of logical
volumes being salvaged.

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.

=head1 OPTIONS

=over 4

=item B<-server> I<machine name>

Indicates the file server machine on which to salvage volumes.
Identify the machine by IP address or its host name (either
fully-qualified or abbreviated unambiguously). For details, see
the introductory reference page for the C<bos> command suite.

=item B<-partition> I<salvage partition>

Specifies a single partition on which to salvage all volumes.
Provide the complete partition name (for example B</vicepa>) or
one of the following abbreviated forms:

  /vicepa     =     vicepa      =      a      =      0
  /vicepb     =     vicepb      =      b      =      1

After B</vicepz> (for which the index is 25) comes

  /vicepaa    =     vicepaa     =      aa     =      26
  /vicepab    =     vicepab     =      ab     =      27

and so on through

  /vicepiv    =     vicepiv     =      iv     =      255

=item B<-volume> I<salvage volume number or volume name>

Specifies the name or volume ID number of a read/write volume
to salvage. The B<-partition> argument must be provided along with
this one.

=item B<-file> I<salvage log output file>

Specifies the complete pathname of a file into which to write a
trace of the salvage operation, in addition to the
B</usr/afs/logs/SalvageLog> file on the server machine. If the
file pathname is local, the trace is written to the specified
file on the local disk of the machine where the C<bos salvage>
command is issued. If the B<-volume> argument is included, the
file can be in AFS, though not in the volume being salvaged. Do
not combine this argument with the B<-showlog> flag.

=item B<-all>

Salvages all volumes on all of the partitions on the machine
named by the B<-server> argument.

=item B<-showlog>

Displays the trace of the salvage operation on the standard
output stream, as well as writing it to the
B</usr/afs/logs/SalvageLog> file. Do not combine this flag with
the B<-file> argument.

=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

=item *

An integer from the range B<1> to B<32>. A value of B<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 B<1> to B<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.

=item B<-tmpdir> I<directory to place tmp files>

Specifies the full pathname of a local disk directory to which
the Salvager process writes temporary files as it runs. If this
argument is omitted, or specifies an ineligible or nonexistent
directory, the Salvager process writes the files to the
partition it is currently salvaging.

=item B<-orphans> I<ignore | remove | attach>

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

=over

=item B<ignore>

Leaves the orphaned objects on the disk, but prints a
message to the B</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 B<remove>

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

=item B<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:

B<_ _ORPHANFILE_ _.>I<index> for files

B<_ _ORPHANDIR_ _.>I<index> for directories

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 C<ls>
command issued against the volume's root directory.

=back

=item B<-cell> I<cell name>

Names the cell in which to run the command. Do not combine this
argument with the B<-localauth> flag. For more details, see the
introductory L<bos(1)> reference page.

=item B<-noauth>

Assigns the unprivileged identity B<anonymous> to the issuer. Do
not combine this flag with the B<-localauth> flag. For more
details, see the introductory L<bos(1)> reference page.

=item B<-localauth>

Constructs a server ticket using a key from the local
B</usr/afs/etc/KeyFile> file. The C<bos> command interpreter presents
the ticket to the BOS Server during mutual authentication. Do
not combine this flag with the B<-cell> or B<-noauth> options. For
more details, see the introductory L<bos(1)> reference page.

=item B<-help>

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

=back

=head1 EXAMPLES

The following command salvages all volumes on the B</vicepd> partition of
the machine B<db3.abc.com>:

    bos salvage -server db3.abc.com -partition /vicepd

The following command salvages the volume with volume ID number
536870988 on partition B</vicepb> of the machine B<fs2.abc.com>:

    bos salvage -server fs2.abc.com -partition /vicepb -volume 536870988

The following command salvages all volumes on the machine B<fs4.abc.com>.
Six Salvager processes run in parallel rather than the default four.

    bos salvage -server fs4.abc.com -all -parallel 6

=head1 PRIVILEGE REQUIRED

The issuer must be listed in the B</usr/afs/etc/UserList> file on the
machine named by the B<-server> argument, or must be logged onto a server
machine as the local superuser B<root> if the B<-localauth> flag is
included.

=head1 CAVEATS

Running this command can result in data loss if the Salvager process
can repair corruption only by removing the offending data. Consult the
IBM AFS Administration Guide for more information.

=head1 COPYRIGHT

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

Converted from html to pod by Alf Wachsmann <alfw@slac.stanford.edu>, 2003,
and Elizabeth Cassell <e_a_c@mailsnare.net>, 2004,
Stanford Linear Accelerator Center, a department of Stanford University.

=head1 SEE ALSO

L<KeyFile(1)>,
L<SalvageLog(1)>,
L<UserList(1)>,
L<bos(1)>,
L<salvager(1)>,
L<vos_backup(1)>,
L<vos_release(1)>,
L<vos_remove(1)>,
L<vos_zap(1)>,
IBM AFS Administration Guide

=cut
