NAME
vos_release - Updates read-only volumes to match the read/write source
volume
SYNOPSIS
vos release -id <volume name or ID> [-f]
[-cell <cell name>] [-noauth] [-localauth] [-verbose]
[-help]
vos rel -i <volume name or ID> [-f] [-c <cell name>]
[-n] [-l] [-v] [-h]
DESCRIPTION
The vos release command copies the contents of the indicated read/write
source volume to each read-only site defined in the source volume’s
Volume Location Database (VLDB) entry. (Use the vos addsite command to
define sites as necessary before issuing this command). Each read-only
copy has the same name as read/write source with the addition of a
".readonly" extension.
For users to have a consistent view of the file system, the release of
the new volume version must be atomic: either all read-only sites
receive the new version, or all sites keep the version they currently
have. The vos release command is designed to ensure that all copies of
the volume’s read-only version match both the read/write source and
each other. In cases where problems such as machine or server process
outages prevent successful completion of the release operation, AFS
uses two mechanisms to alert the administrator.
First, the command interpreter generates an error message on the
standard error stream naming each read-only site that did not receive
the new volume version. Second, during the release operation the Volume
Location (VL) Server marks site definitions in the VLDB entry with
flags ("New release" and "Old release") that indicate whether or not
the site has the new volume version. If any flags remain after the
operation completes, it was not successful. The Cache Manager refuses
to access a read-only site marked with the "Old release" flag, which
potentially imposes a greater load on the sites marked with the "New
release" flag. It is important to investigate and eliminate the cause
of the failure and then to issue the vos release command as many times
as necessary to complete the release without errors.
The pattern of site flags remaining in the volume’s VLDB entry after a
failed release operation can help determine the point at which the
operation failed. Use the vos examine or vos listvldb command to
display the VLDB entry. The VL Server sets the flags in concert with
the Volume Server’s operations, as follows:
· Before the operation begins, the VL Server sets the "New release"
flag on the read/write site definition in the VLDB entry and the
"Old release" flag on read-only site definitions (unless the read-
only site has been defined since the last release operation and has
no actual volume, in which case its site flag remains "Not
released").
· If necessary, the Volume Server creates a temporary copy (a clone)
of the read/write source called the ReleaseClone (see the following
discussion of when the Volume Server does or does not create a new
ReleaseClone.) It assigns the ReleaseClone its own volume ID
number, which the VL Server records in the "RClone" field of the
source volume’s VLDB entry.
· The Volume Server distributes a copy of the ReleaseClone to each
read-only site defined in the VLDB entry. As the site successfully
receives the new clone, the VL Server sets the site’s flag in the
VLDB entry to "New release".
· When all the read-only copies are successfully released, the VL
Server clears all the "New release" site flags. The ReleaseClone is
no longer needed, so the Volume Server deletes it and the VL Server
erases its ID from the VLDB entry.
By default, the Volume Server determines automatically whether or not
it needs to create a new ReleaseClone:
· If there are no flags ("New release", "Old release", or "Not
released") on site definitions in the VLDB entry, the previous vos
release command completed successfully and all read-only sites
currently have the same volume. The Volume Server infers that the
current vos release command was issued because the read/write
volume has changed. The Volume Server creates a new ReleaseClone
and distributes it to all of the read-only sites.
· If any site definition in the VLDB entry is marked with a flag,
either the previous release operation did not complete successfully
or a new read-only site was defined since the last release. The
Volume Server does not create a new ReleaseClone, instead
distributing the existing ReleaseClone to sites marked with the
"Old release" or "Not released" flag. As previously noted, the VL
Server marks each VLDB site definition with the "New release" flag
as the site receives the ReleaseClone, and clears all flags after
all sites successfully receive it.
To override the default behavior, forcing the Volume Server to create
and release a new ReleaseClone to the read-only sites, include the -f
flag. This is appropriate if, for example, the data at the read/write
site has changed since the existing ReleaseClone was created during the
previous release operation.
OPTIONS
-id <volume name or id>
Specifies either the complete name or volume ID number of a
read/write volume.
-f Creates a new ReleaseClone and distributes it all read-only sites
regardless of whether or not any site definitions in the VLDB entry
are marked with a flag.
-cell <cell name>
Names the cell in which to run the command. Do not combine this
argument with the -localauth flag. For more details, see vos(1).
-noauth
Assigns the unprivileged identity "anonymous" to the issuer. Do not
combine this flag with the -localauth flag. For more details, see
vos(1).
-localauth
Constructs a server ticket using a key from the local
/etc/openafs/server/KeyFile file. The vos command interpreter
presents it to the Volume Server and Volume Location Server during
mutual authentication. Do not combine this flag with the -cell
argument or -noauth flag. For more details, see vos(1).
-verbose
Produces on the standard output stream a detailed trace of the
command’s execution. If this argument is omitted, only warnings and
error messages appear.
-help
Prints the online help for this command. All other valid options
are ignored.
EXAMPLES
The following command clones the read/write volume usr and releases it
to the read-only sites defined in its VLDB entry.
% vos release usr
PRIVILEGE REQUIRED
The issuer must be listed in the /etc/openafs/server/UserList file on
the machine specified with the -server argument and on each database
server machine. If the -localauth flag is included, the issuer must
instead be logged on to a server machine as the local superuser "root".
SEE ALSO
vos(1), vos_addsite(1), vos_examine(1), vos_listvldb(1)
COPYRIGHT
IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
This documentation is covered by the IBM Public License Version 1.0.
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and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.