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Provided by: openafs-client_1.4.4-1_i386

 

NAME

        afsd - Initializes the Cache Manager and starts related daemons
 

SYNOPSIS

        afsd [-blocks <1024 byte blocks in cache>]
             [-files <files in cache>]
             [-rootvol <name of AFS root volume>]
             [-stat <number of stat entries>]
             [-memcache] [-cachedir <cache directory>]
             [-mountdir <mount location>]
             [-daemons <number of daemons to use>]
             [-nosettime] [-verbose] [-rmtsys] [-debug]
<log(2) of chunk size>]
             [-dcache <number of dcache entries>]
             [-volumes <number of volume entries>]
             [-biods <number of bkg I/O daemons (aix vm)>]
             [-prealloc <number of ’small’ preallocated blocks>]
             [-confdir <configuration directory>]
             [-logfile <Place to keep the CM log>]
             [-waitclose] [-shutdown] [-enable_peer_stats]
             [-enable_process_stats] [-help]
 

DESCRIPTION

        The afsd command initializes the Cache Manager on an AFS client machine
        by transferring AFS-related configuration information into kernel mem‐
        ory and starting several daemons. More specifically, the afsd command
        performs the following actions:
 
        ·   Sets a field in kernel memory that defines the machine’s cell mem‐
            bership. Some Cache Manager-internal operations and system calls
            consult this field to learn which cell to execute in. (The AFS com‐
            mand interpreters refer to the /etc/openafs/ThisCell file instead.)
            This information is transferred into the kernel from the /etc/ope‐
            nafs/ThisCell file and cannot be changed until the afsd program
            runs again.
 
        ·   Places in kernel memory the names and Internet addresses of the
            database server machines in the local cell and (optionally) foreign
            cells. The appearance of a cell’s database server machines in this
            list enables the Cache Manager to contact them and to access files
            in the cell. Omission of a cell from this list, or incorrect infor‐
            mation about its database server machines, prevents the Cache Man‐
            ager from accessing files in it.
 
            The list of database server machines is transferred into the kernel
            from the /etc/openafs/CellServDB file. After initialization, use
            the fs newcell command to change the kernel-resident list without
            having to reboot.
 
        ·   Mounts the root of the AFS filespace on a directory on the
            machine’s local disk, according to either the first field in the
            /etc/openafs/cacheinfo file (the default) or the afsd command’s
            -mountdir argument. The conventional value is /afs.
 
        ·   Determines which volume to mount at the root of the AFS file tree.
            The default is the volume "root.afs"; use the -rootvol argument to
            override it. Although the base (read/write) form of the volume name
            is the appropriate value, the Cache Manager has a bias for access‐
            ing the read-only version of the volume (by convention,
            "root.afs.readonly") if it is available.
 
        ·   Configures the cache on disk (the default) or in machine memory if
            the -memcache argument is provided. In the latter case, the afsd
            program allocates space in machine memory for caching, and the
            Cache Manager uses no disk space for caching even if the machine
            has a disk.
 
        ·   Defines the name of the local disk directory devoted to caching,
            when the -memcache argument is not used. If necessary, the afsd
            program creates the directory (its parent directory must already
            exist). It does not remove the directory that formerly served this
            function, if one exists.
 
            The second field in the /etc/openafs/cacheinfo file is the source
            for this name, and the standard value is the /usr/vice/cache direc‐
            tory. Use the -cachedir argument to override the value in the
            cacheinfo file.
 
        ·   Sets the size of the cache. The default source for the value is the
            third field in the /etc/openafs/cacheinfo file, which specifies a
            number of kilobytes.
 
            For a memory cache, the following arguments to the afsd command
            override the value in the cacheinfo file:
 
            ·   The -blocks argument, to specify a different number of kilobyte
                blocks.
 
            ·   The -dcache and -chunksize arguments together, to set both the
                number of dcache entries and the chunk size (see below for def‐
                inition of these parameters). In this case, the afsd program
                derives cache size by multiplying the two values. Using this
                combination is not recommended, as it requires the issuer to
                perform the calculation beforehand to determine the resulting
                cache size.
 
            ·   The -dcache argument by itself. In this case, the afsd program
                derives cache size by multiplying the value specified by the
                -dcache argument by the default memory cache chunk size of
                eight kilobytes. Using this argument is not recommended, as it
                requires the issuer to perform the calculation beforehand to
                determine the resulting cache size.
 
            For satisfactory memory cache performance, the specified value must
            leave enough memory free to accommodate all other processes and
            commands that can run on the machine. If the value exceeds the
            amount of memory available, the afsd program exits without initial‐
            izing the Cache Manager and produces the following message on the
            standard output stream:
 
               afsd: memCache allocation failure at <number> KB
 
            where <number> is how many kilobytes were allocated just before the
            failure.
 
            For a disk cache, use the -blocks argument to the afsd command to
            override the value in the cacheinfo file. The value specified in
            either way sets an absolute upper limit on cache size; values pro‐
            vided for other arguments (such as -dcache and -chunksize) never
            result in a larger cache. The afsd program rejects any setting
            larger than 95% of the partition size, and exits after generating
            an error message on the standard output stream, because the cache
            implementation itself requires a small amount of disk space and
            overfilling the partition can cause the client machine to panic.
 
            To change the size of a disk cache after initialization without
            rebooting, use the fs setcachesize command; the setting persists
            until the afsd command runs again or the fs setcachesize command is
            reissued. The fs setcachesize command does not work for memory
            caches.
 
        ·   Sets the size of each cache chunk, and by implication the amount of
            data that the Cache Manager requests at a time from the File Server
            (how much data per fetch RPC, since AFS uses partial file trans‐
            fer).
 
            For a disk cache, a chunk is a Vn file and this parameter sets the
            maximum size to which each one can expand; the default is 64 KB.
            For a memory cache, each chunk is a collection of contiguous memory
            blocks; the default is size is 8 KB.
 
            To override the default chunk size for either type of cache, use
            the -chunksize argument to provide an integer to be used as an
            exponent of two; see OPTIONS for details. For a memory cache, if
            total cache size divided by chunk size leaves a remainder, the afsd
            program rounds down the number of dcache entries, resulting in a
            slightly smaller cache.
 
        ·   Sets the number of chunks in the cache. For a memory cache, the
            number of chunks is equal to the cache size divided by the chunk
            size.  For a disk cache, the number of chunks (Vn files) is set to
            the largest of the following unless the -files argument is used to
            set the value explicitly:
 
            ·   100
 
            ·   1.5 times the result of dividing cache size by chunk size
                (cachesize/chunksize * 1.5)
 
            ·   The result of dividing cachesize by 10 KB (cachesize/10240)
 
        ·   Sets the number of dcache entries allocated in machine memory for
            storing information about the chunks in the cache.
 
            For a disk cache, the /usr/vice/cache/CacheItems file contains one
            entry for each Vn file. By default, one half the number of these
            entries (but not more that 2,000) are duplicated as dcache entries
            in machine memory for quicker access.
 
            For a memory cache, there is no CacheItems file so all information
            about cache chunks must be in memory as dcache entries.  Thus,
            there is no default number of dcache entries for a memory cache;
            instead, the afsd program derives it by dividing the cache size by
            the chunk size.
 
            To set the number of dcache entries, use the -dcache argument; the
            specified value can exceed the default limit of 2,000. Using this
            argument is not recommended for either type of cache. Increasing
            the number of dcache entries for a disk cache sometimes improves
            performance (because more entries are retrieved from memory rather
            than from disk), but only marginally. Using this argument for a
            memory cache requires the issuer to calculate the cache size by
            multiplying this value by the chunk size.
 
        ·   Sets the number of stat entries available in machine memory for
            caching status information about cached AFS files. The default is
            300; use the -stat argument to override the default.
 
        ·   Randomly selects a file server machine in the local cell as the
            source for the correct time. Every five minutes thereafter, the
            local clock is adjusted (if necessary) to match the file server
            machine’s clock.
 
            Use the -nosettime flag to prevent the afsd command from selecting
            a time standard. This is recommended only on file server machines
            that are also acting as clients. File server machines maintain the
            correct time using the Network Time Protocol Daemon instead.
 
        In addition to setting cache configuration parameters, the afsd program
        starts the following daemons. (On most system types, these daemons
        appear as nameless entries in the output of the UNIX ps command.)
 
        ·   One callback daemon, which handles callbacks. It also responds to
            the File Server’s periodic probes, which check that the client
            machine is still alive.
 
        ·   One maintenance daemon, which performs the following tasks:
 
            ·   Garbage collects obsolete data (for example, expired tokens)
                from kernel memory.
 
            ·   Synchronizes files.
 
            ·   Refreshes information from read-only volumes once per hour.
 
            ·   Does delayed writes for NFS clients if the machine is running
                the NFS/AFS Translator.
 
        ·   One cache-truncation daemon, which flushes the cache when free
            space is required, by writing cached data and status information to
            the File Server.
 
        ·   One server connection daemon, which sends a probe to the File
            Server every few minutes to check that it is still accessible. It
            also synchronizes the machine’s clock with the clock on a randomly-
            chosen file server machine, unless the -nosettime flag is used.
            There is always one server connection daemon.
 
        ·   One or more background daemons that improve performance by pre-
            fetching files and performing background (delayed) writes of saved
            data into AFS.
 
            The default number of background daemons is two, enough to service
            at least five simultaneous users of the machine. To increase the
            number, use the -daemons argument. A value greater than six is not
            generally necessary.
 
        ·   On some system types, one Rx listener daemon, which listens for
            incoming RPCs.
 
        ·   On some system types, one Rx event daemon, which reviews the Rx
            system’s queue of tasks and performs them as appropriate. Most
            items in the queue are retransmissions of failed packets.
 
        ·   On machines that run AIX with virtual memory (VM) integration, one
            or more VM daemons (sometimes called I/O daemons, which transfer
            data between disk and machine memory. The number of them depends on
            the setting of the -biods and -daemons arguments:
 
            ·   If the -biods argument is used, it sets the number of VM dae‐
                mons.
 
            ·   If only the -daemons argument is used, the number of VM daemons
                is twice the number of background daemons.
 
            ·   If neither argument is used, there are five VM daemons.
 
        This command does not use the syntax conventions of the AFS command
        suites. Provide the command name and all option names in full.
 

CAUTIONS

        Before using the -shutdown parameter, use the standard UNIX umount com‐
        mand to unmount the AFS root directory (by convention, /afs).  On
        Linux, unloading the AFS kernel module and then loading it again before
        restarting AFS after -shutdown is recommended.
 
        AFS has for years had difficulties with being stopped and restarted
        without an intervening reboot.  While most of these issues have been
        ironed out, stopping and restarting AFS is not recommended unless nec‐
        essary and rebooting before restarting AFS is still the safest course
        of action.
 

OPTIONS

        -blocks <blocks in cache>
            Specifies the number of kilobyte blocks to be made available for
            caching in the machine’s cache directory (for a disk cache) or mem‐
            ory (for a memory cache), overriding the default defined in the
            third field of the /etc/openafs/cacheinfo file. For a disk cache,
            the value cannot exceed 95% of the space available in the cache
            partition. If using a memory cache, do not combine this argument
            with the -dcache argument, since doing so can possibly result in a
            chunk size that is not an exponent of 2.
 
        -files <files in cache>
            Specifies the number of Vn files to create in the cache directory
            for a disk cache, overriding the default that is calculated as
            described in DESCRIPTION. Each Vn file accommodates a chunk of
            data, and can grow to a maximum size of 64 KB by default. Do not
            combine this argument with the -memcache argument.
 
        -rootvol <name of AFS root volume>
            Names the read/write volume corresponding to the root directory for
            the AFS file tree (which is usually the /afs directory). This value
            overrides the default of the "root.afs" volume.
 
        -stat <number of stat entries>
            Specifies the number of entries to allocate in the machine’s memory
            for recording status information about the AFS files in the cache.
            This value overrides the default of 300.
 
        -memcache
            Initializes a memory cache rather than a disk cache. Do not combine
            this flag with the -files argument.
 
        -cachedir <cache directory>
            Names the local disk directory to be used as the cache. This value
            overrides the default defined in the second field of the /etc/ope‐
            nafs/cacheinfo file.
 
        -mountdir <mount location>
            Names the local disk directory on which to mount the root of the
            AFS filespace. This value overrides the default defined in the
            first field of the /etc/openafs/cacheinfo file. If a value other
            than the /afs directory is used, the machine cannot access the
            filespace of cells that do use that value.
 
        -daemons <number of daemons to use>
            Specifies the number of background daemons to run on the machine.
            These daemons improve efficiency by doing prefetching and back‐
            ground writing of saved data. This value overrides the default of
            2, which is adequate for a machine serving up to five users. Values
            greater than 6 are not generally more effective than 6.
 
            Note: On AIX machines with integrated virtual memory (VM), the num‐
            ber of VM daemons is set to twice the value of this argument, if it
            is provided and the -biods argument is not. If both arguments are
            omitted, there are five VM daemons.
 
        -nosettime
            Prevents the Cache Manager from synchronizing its clock with the
            clock on a server machine selected at random, by checking the time
            on the server machine every five minutes. Use this flag only on a
            machine that is already using another time synchronization protocol
            (for example, a server machine that is running the runntp process).
 
        -verbose
            Generates a detailed trace of the afsd program’s actions on the
            standard output stream.
 
        -rmtsys
            Initializes an additional daemon to execute AFS-specific system
            calls on behalf of NFS client machines. Use this flag only if the
            machine is an NFS/AFS translator machine serving users of NFS
            client machines who execute AFS commands.
 
        -debug
            Generates a highly detailed trace of the afsd program’s actions on
            the standard output stream. The information is useful mostly for
            debugging purposes.
 
        -chunksize <chunk size>
            Sets the size of each cache chunk. The integer provided, which must
            be from the range 0 to 30, is used as an exponent on the number 2.
            It overrides the default of 16 for a disk cache (2^16 is 64 KB) and
            13 for a memory cache (2^13 is 8 KB). A value of 0 or less, or
            greater than 30, sets chunk size to the appropriate default. Values
            less than 10 (which sets chunk size to a 1 KB) are not recommended.
            Combining this argument with the -dcache argument is not recom‐
            mended because it requires that the issuer calculate the cache size
            that results.
 
        -dcache <number of dcache entries>
            Sets the number of dcache entries in memory, which are used to
            store information about cache chunks. For a disk cache, this over‐
            rides the default, which is 50% of the number of Vn files (cache
            chunks). For a memory cache, this argument effectively sets the
            number of cache chunks, but its use is not recommended, because it
            requires the issuer to calculate the resulting total cache size
            (derived by multiplying this value by the chunk size). Do not com‐
            bine this argument with the -blocks argument, since doing so can
            possibly result in a chunk size that is not an exponent of 2.
 
        -volumes <number of volume entries>
            Specifies the number of memory structures to allocate for storing
            volume location information. The default value is 50.
 
        -biods <number of I/O daemons>
            Sets the number of VM daemons dedicated to performing I/O opera‐
            tions on a machine running a version of AIX with virtual memory
            (VM) integration.  If both this argument and the -daemons argument
            are omitted, the default is five. If this argument is omitted but
            the -daemons argument is provided, the number of VM daemons is set
            to twice the value of the -daemons argument.
 
        -prealloc <number of preallocated blocks>
            Specifies the number of pieces of memory to preallocate for the
            Cache Manager’s internal use. The default initial value is 400, but
            the Cache Manager dynamically allocates more memory as it needs it.
 
        -confdir <configuration directory>
            Names a directory other than the /etc/openafs directory from which
            to fetch the cacheinfo, ThisCell, and CellServDB configuration
            files.
 
        -logfile <log file location>
            Is obsolete and has no real effect. It specifies an alternate file
            in which to record a type of trace that the Cache Manager no longer
            generates; the default value is /etc/openafs/AFSLog.
 
        -waitclose
            Has no effect on the operation of the Cache Manager. The behavior
            it affected in previous versions of the Cache Manager, to perform
            synchronous writes to the File Server, is now the default behavior.
            To perform asynchronous writes in certain cases, use the fs store     
            behind command.
 
        -shutdown
            Shuts down the Cache Manager, but not in the most effective possi‐
            ble way. Do not use this flag.
 
        -enable_peer_stats
            Activates the collection of Rx statistics and allocates memory for
            their storage. For each connection with a specific UDP port on
            another machine, a separate record is kept for each type of RPC
            (FetchFile, GetStatus, and so on) sent or received. To display or
            otherwise access the records, use the Rx Monitoring API.
 
        -enable_process_stats
            Activates the collection of Rx statistics and allocates memory for
            their storage. A separate record is kept for each type of RPC
            (FetchFile, GetStatus, and so on) sent or received, aggregated over
            all connections to other machines. To display or otherwise access
            the records, use the Rx Monitoring API.
 
        -help
            Prints the online help for this command. All other valid options
            are ignored.
 

EXAMPLES

        The afsd command is normally included in the machine’s AFS initializa‐
        tion file, rather than typed at the command shell prompt. For most disk
        caches, the appropriate form is
 
           /etc/openafs/afsd
 
        The following command is appropriate when enabling a machine to act as
        an NFS/AFS Translator machine serving more than five users.
 
           /etc/openafs/afsd -daemons 4 -rmtsys
 
        The following command initializes a memory cache and sets chunk size to
        16 KB (2^14).
 
           /etc/openafs/afsd -memcache -chunksize 14
        The issuer must be logged in as the local superuser root.
cacheinfo(5)
 

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.
 

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