CernVM-FS Parameters

Client parameters

Parameters recognized in configuration files under /etc/cvmfs:

Parameter	Meaning
CVMFS_ALIEN_CACHE	If set, use an alien cache at the given location
CVMFS_ALT_ROOT_PATH	If set to yes, use alternative root catalog path. Only required for fixed catalogs (tag / hash) under the alternative path.
CVMFS_AUTO_UPDATE	If set to no, disables the automatic update of file catalogs.
CVMFS_AUTHZ_HELPER	Full path to an authz helper, overwrites the helper hint in the catalog.
CVMFS_AUTHZ_SEARCH_PATH	Full path to the directory that contains the authz helpers.
CVMFS_BACKOFF_INIT	Seconds for the maximum initial backoff when retrying to download data.
CVMFS_BACKOFF_MAX	Maximum backoff in seconds when retrying to download data.
CVMFS_CATALOG_WATERMARK	Try to release pinned catalogs when their number surpasses the given watermark. Defaults to 1/4 CVMFS_NFILES; explicitly set by shrinkwrap.
CVMFS_CACHE_BASE	Location (directory) of the CernVM-FS cache.
CVMFS_CACHE_REFCOUNT	If set to yes, deduplicate open file descriptors by refcounting.
CVMFS_CACHE_SYMLINKS	If set to yes, enables symlink caching in the kernel.
CVMFS_CHECK_PERMISSIONS	If set to no, disable checking of file ownership and permissions (open all files).
CVMFS_CLAIM_OWNERSHIP	If set to yes, allows CernVM-FS to claim ownership of files and directories.
CVMFS_CPU_AFFINITY	Comma-separated list to set CPU affinity for all cvmfs components.
CVMFS_DEBUGLOG	If set, run CernVM-FS in debug mode and write a verbose log the the specified file.
CVMFS_DEFAULT_DOMAIN	The default domain will be automatically appended to repository names when given without a domain.
CVMFS_DNS_MIN_TTL	Minimum effective TTL in seconds for DNS queries of proxy server names (not Stratum 1s). Defaults to 1 minute.
CVMFS_DNS_MAX_TTL	Maximum effective TTL in seconds for DNS queries of proxy server names (not Stratum 1s). Defaults to 1 day.
CVMFS_DNS_RETRIES	Number of retries when resolving proxy names
CVMFS_DNS_TIMEOUT	Timeout in seconds when resolving proxy names
CVMFS_DNS_ROAMING	If true, watch /etc/resolv.conf for nameserver changes
CVMFS_ENFORCE_ACLS	Enforce POSIX ACLs stored in the repository. Requires libfuse 3.
CVMFS_EXTERNAL_FALLBACK_PROXY	List of HTTP proxies similar to CVMFS_EXTERNAL_HTTP_PROXY. The fallback proxies are added to the end of the normal proxies, and disable DIRECT connections.
CVMFS_EXTERNAL_HTTP_PROXY	Chain of HTTP proxy groups to be used when CernVM-FS is accessing external data
CVMFS_EXTERNAL_MAX_SERVERS	Caps the list of external hosts to the given number (after geo-sorting them)
CVMFS_EXTERNAL_TIMEOUT	Timeout in seconds for HTTP requests to an external-data server with a proxy server
CVMFS_EXTERNAL_TIMEOUT_DIRECT	Timeout in seconds for HTTP requests to an external-data server without a proxy server
CVMFS_EXTERNAL_URL	Semicolon-separated chain of webservers serving external data chunks.
CVMFS_FALLBACK_PROXY	List of HTTP proxies similar to CVMFS_HTTP_PROXY. The fallback proxies are added to the end of the normal proxies, and disable DIRECT connections.
CVMFS_FOLLOW_REDIRECTS	When set to yes, follow up to 4 HTTP redirects in requests.
CVMFS_HIDE_MAGIC_XATTRS	If set to yes the client will not expose CernVM-FS specific extended attributes
CVMFS_HOST_RESET_AFTER	See CVMFS_PROXY_RESET_AFTER.
CVMFS_HTTP_PROXY	Chain of HTTP proxy groups used by CernVM-FS. Necessary. Set to DIRECT if you don’t use proxies.
CVMFS_IGNORE_SIGNATURE	When set to yes, don’t verify CernVM-FS file catalog signatures.
CVMFS_INITIAL_GENERATION	Initial inode generation. Used for testing.
CVMFS_INSTRUMENT_FUSE	When set to true gather performance statistics about the FUSE callbacks. The results are displayed with cvmfs_talk internal affairs.
CVMFS_NFS_INTERLEAVED_INODES	In NFS mode, use only inodes of the form \(an+b\), specified as “b%a”.
CVMFS_INFLUX_EXTRA_FIELDS	Static fields always attached to the (absolute) output of the InfluxDB Telemetry Aggregator
CVMFS_INFLUX_EXTRA_TAGS	Static tags always attached to the (absolute + delta) output of the InfluxDB Telemetry Aggregator
CVMFS_INFLUX_HOST	Host name or IP address of the receiver of the InfluxDB Telemetry Aggregator
CVMFS_INFLUX_METRIC_NAME	Name of the measurement of the InfluxDB Telemetry Aggregator
CVMFS_INFLUX_PORT	Port of the host (receiver) of the InfluxDB Telemetry Aggregator
CVMFS_IPFAMILY_PREFER	Which IP protocol to prefer when connecting to proxies. Can be either 4 or 6.
CVMFS_KCACHE_TIMEOUT	Timeout in seconds for path names and file attributes in the kernel file system buffers.
CVMFS_KEYS_DIR	Directory containing *.pub files used as repository signing keys. If set, this parameter has precedence over CVMFS_PUBLIC_KEY.
CVMFS_LOW_SPEED_LIMIT	Minimum transfer rate in bytes/second a server or proxy must provide.
CVMFS_MAX_EXTERNAL_SERVERS	Limit the number of (geo sorted) stratum 1 servers for external data that are effectively used.
CVMFS_MAX_IPADDR_PER_PROXY	Limit the number of IP addresses a proxy names resolves into. From all registered addresses, up to the limit are randomly selected.
CVMFS_MAX_RETRIES	Maximum number of retries for a given proxy/host combination.
CVMFS_MAX_SERVERS	Limit the number of (geo sorted) stratum 1 servers that are effectively used.
CVMFS_MAX_TTL	Maximum file catalog TTL in minutes. Can overwrite the TTL stored in the catalog.
CVMFS_MEMCACHE_SIZE	Size of the CernVM-FS metadata memory cache in Megabyte.
CVMFS_MOUNT_RW	Mount CernVM-FS as a read/write file system. Write operations will fail but this option can workaround faulty open() flags.
CVMFS_NFILES	Maximum number of open file descriptors that can be used by the CernVM-FS process.
CVMFS_NFS_SOURCE	If set to yes, act as a source for the NFS daemon (NFS export).
CVMFS_NFS_SHARED	If set a path, used to store the NFS maps in an SQlite database, instead of the usual LevelDB storage in the cache directory.
CVMFS_PAC_URLS	Chain of URLs pointing to PAC files with HTTP proxy configuration information.
CVMFS_OOM_SCORE_ADJ	Set the Linux kernel’s out-of-memory killer priority for the CernVM-FS client [-1000 - 1000].
CVMFS_PROXY_RESET_AFTER	Delay in seconds after which CernVM-FS will retry the primary proxy group in case of a fail-over to another group.
CVMFS_PROXY_SHARD	If set to yes, shard requests across all proxies within the current load-balancing group using consistent hashing.
CVMFS_PROXY_TEMPLATE	Overwrite the default proxy template in Geo-API calls. Only needed for debugging.
CVMFS_PUBLIC_KEY	Colon-separated list of repository signing keys.
CVMFS_QUOTA_LIMIT	Soft-limit of the cache in Megabyte.
CVMFS_RELOAD_SOCKETS	Directory of the sockets used by the CernVM-FS loader to trigger hotpatching/reloading.
CVMFS_REPOSITORIES	Comma-separated list of fully qualified repository names to include in use of client utilities such as cvmfs_talk and cvmfs_config. Does not limit which repositories may be mounted, unless CVMFS_STRICT_MOUNT is set to yes.
CVMFS_REPOSITORY_DATE	A timestamp in ISO format (e.g. 2007-03-01T13:00:00Z). Selects the repository state as of the given date.
CVMFS_REPOSITORY_TAG	Select a named repository snapshot that should be mounted instead of trunk.
CVMFS_CONFIG_REPO_REQUIRED	If set to yes, no repository can be mounted unless the config repository is available.
CVMFS_ROOT_HASH	Hash of the root file catalog, implies CVMFS_AUTO_UPDATE=no.
CVMFS_SEND_INFO_HEADER	If set to yes, include the cvmfs path of downloaded data in HTTP headers.
CVMFS_SERVER_CACHE_MODE	Enable special cache semantics for a client used as a publisher’s repository base line.
CVMFS_SERVER_URL	Semicolon-separated chain of Stratum~1 servers.
CVMFS_SHARED_CACHE	If set to no, makes a repository use an exclusive cache.
CVMFS_STREAMING_CACHE	If set to yes, use a download manager to download regular files on read.
CVMFS_STRICT_MOUNT	If set to yes, mount only repositories that are listed in CVMFS_REPOSITORIES.
CVMFS_SUID	If set to yes, enable suid magic on the mounted repository. Requires mounting as root.
CVMFS_SYSLOG_FACILITY	If set to a number between 0 and 7, uses the corresponding LOCAL$n$ facility for syslog messages.
CVMFS_SYSLOG_LEVEL	If set to 1 or 2, sets the syslog level for CernVM-FS messages to LOG_DEBUG or LOG_INFO respectively.
CVMFS_SYSTEMD_NOKILL	If set to yes, modify the command line to @vmfs2 ... in order to act as a systemd lowlevel storage manager.
CVMFS_TELEMETRY_RATE	Rate in seconds for Telemetry Aggregator to send the telemetry. Minimum send rate >= 5 sec.
CVMFS_TELEMETRY_SEND	ON to activate Telemetry Aggregator.
CVMFS_TIMEOUT	Timeout in seconds for HTTP requests with a proxy server.
CVMFS_TIMEOUT_DIRECT	Timeout in seconds for HTTP requests without a proxy server.
CVMFS_TRACEFILE	If set, enables the tracer and trace file system calls to the given file.
CVMFS_USE_GEOAPI	Request order of Stratum 1 servers and fallback proxies via Geo-API.
CVMFS_USE_SSL_SYSTEM_CA	When connecting to an HTTPS endpoints, it will load the certificates provided by the system.
CVMFS_USER	Sets the gid and uid mount options. Don’t touch or overwrite.
CVMFS_USYSLOG	All messages that normally are logged to syslog are re-directed to the given file. This file can grow up to 500kB and there is one step of log rotation. Required for $mu$CernVM.
CVMFS_XATTR_PRIVILEGED_GIDS	Comma-separated list of (main) group IDs that are allowed to access the extended attributes listed by CVMFS_XATTR_PROTECTED_XATTRS.
CVMFS_XATTR_PROTECTED_XATTRS	Comma-separated list of extended attributes (full name, e.g. user.fqrn) that are only accessible by root and the group IDs listed by CVMFS_XATTR_PRIVILEGED_GIDS.
CVMFS_WORKSPACE	Set the local directory for storing special files (defaults to the cache directory).
CVMFS_WORLD_READABLE	Override posix read permissions to make files in repository globally readable

Server parameters

Parameter	Meaning
CVMFS_AUFS_WARNING	Set to false to silence AUFS kernel deadlock warning.
CVMFS_AUTO_GC	Enables the automatic garbage collection on publish and snapshot
CVMFS_AUTO_GC_TIMESPAN	Date-threshold for automatic garbage collection (For example: 3 days ago, 1 week ago, …)
CVMFS_AUTO_GC_LAPSE	Frequency of auto garbage collection, only garbage collect if last GC is before the given threshold (For example: 1 day ago)
CVMFS_AUTO_REPAIR_MOUNTPOINT	Set to true to enable automatic recovery from bogus server mount states.
CVMFS_AUTO_TAG	Creates a generic revision tag for each published revision (if set to true).
CVMFS_AUTO_TAG_TIMESPAN	Date-threshold for automatic tags, after which auto tags get removed (For example: 4 days ago)
CVMFS_AUTOCATALOGS	Enable/disable automatic catalog management using autocatalogs.
CVMFS_AUTOCATALOGS_MAX_WEIGHT	Maximum number of entries in an autocatalog to be considered overflowed. Default value: 100000 (see also CVMFS_AUTOCATALOGS)
CVMFS_AUTOCATALOGS_MIN_WEIGHT	Minimum number of entries in an autocatalog to be considered underflowed. Default value: 1000 (see also CVMFS_AUTOCATALOGS)
CVMFS_AVG_CHUNK_SIZE	Desired Average size of a file chunk in bytes (see also CVMFS_USE_FILE_CHUNKING)
CVMFS_CATALOG_ALT_PATHS	Enable/disable generation of catalog bootstrapping shortcuts during publishing. (Useful when backend directory /data is not publicly accessible)
CVMFS_CHECK_ALL_MIN_DAYS	Minimum number of days between checking each repository with cvmfs_server check -a Default value: 30
CVMFS_COMPRESSION_ALGORITHM	Compression algorithm to be used during publishing (currently either ‘default’ or ‘none’)
CVMFS_CREATOR_VERSION	The CernVM-FS version that was used to create this repository (do not change manually).
CVMFS_DONT_CHECK_OVERLAYFS_VERSION	Disable checking of OverlayFS version before usage. (see Requirements for a new Repository)
CVMFS_ENFORCE_LIMITS	Set to true to cause exceeding *LIMIT variables to be fatal to a publish instead of a warning
CVMFS_EXTENDED_GC_STATS	Set to true to keep track of the volume of garbage collected files (increases GC running time)
CVMFS_EXTERNAL_DATA	Set to true to mark repository to contain external data that is served from an external HTTP server
CVMFS_FILE_MBYTE_LIMIT	Maximum number of megabytes for a published file, default value: 1024 (see also CVMFS_ENFORCE_LIMITS)
CVMFS_FORCE_REMOUNT_WARNING	Enable/disable warning through wall and grace period before forcefully remounting a CernVM-FS repository on the release managere machine.
CVMFS_GARBAGE_COLLECTION	Enables repository garbage collection (Stratum~0 only | if set to true)
CVMFS_GC_DELETION_LOG	Log file path to track all garbage collected objects during sweeping for bookkeeping or debugging
CVMFS_GEO_ACCOUNT_ID	Account id for downloading the geolite2 city database from maxmind.
CVMFS_GEO_DB_FILE	Path to externally updated location of geolite2 city database, or ‘None’ for no database.
CVMFS_GEO_LICENSE_KEY	A license key for downloading the geolite2 city database from maxmind.
CVMFS_GID_MAP	Path of a file for the mapping of file owner group ids.
CVMFS_HASH_ALGORITHM	Define which secure hash algorithm should be used by CernVM-FS for CAS objects (supported are: sha1, rmd160 and shake128)
CVMFS_HTTP_TRACING	Activates that a tracing header is attached to each CURL request. Consists of uid, pid, and gid. Default is off.
CVMFS_HTTP_TRACING_HEADERS	Adds additional static, user-defined tracing headers. Format: key1:val1|key2:val2|key3:val3. Needs CVMFS_HTTP_TRACING to be set to on.
CVMFS_IGNORE_SPECIAL_FILES	Set to true to skip special files (pipes, sockets, block device and character device files) during publish without aborting.
CVMFS_INCLUDE_XATTRS	Set to true to process extended attributes
CVMFS_MAX_CHUNK_SIZE	Maximal size of a file chunk in bytes (see also CVMFS_USE_FILE_CHUNKING)
CVMFS_MAXIMAL_CONCURRENT_WRITES	Maximal number of concurrently processed files during publishing.
CVMFS_MIN_CHUNK_SIZE	Minimal size of a file chunk in bytes (see also CVMFS_USE_FILE_CHUNKING)
CVMFS_NESTED_KCATALOG_LIMIT	Maximum thousands of files allowed in nested catalogs, default 500 (see also CVMFS_ROOT_KCATALOG_LIMIT and CVMFS_ENFORCE_LIMITS)
CVMFS_NUM_UPLOAD_TASKS	Number of threads used to commit data to storage during publication. Currently only used by the local backend.
CVMFS_NUM_WORKERS	Maximal number of concurrently downloaded files during a Stratum1 pull operation (Stratum~1 only).
CVMFS_PUBLIC_KEY	Colon-separated path to the public key file(s) or directory(ies) of the repository to be replicated. (Stratum 1 only).
CVMFS_PRINT_STATISTICS	Set to true to show publisher statistics on the console
CVMFS_REPLICA_ACTIVE	Stratum1-only: Set to no to skip this repository when executing cvmfs_server snapshot -a
CVMFS_REPOSITORY_NAME	The fully qualified name of the specific repository.
CVMFS_REPOSITORY_TYPE	Defines if the repository is a master copy (stratum0) or a replica (stratum1).
CVMFS_REPOSITORY_TTL	The frequency in seconds of client lookups for changes in the repository. Defaults to 4 minutes.
CVMFS_ROOT_KCATALOG_LIMIT	Maximum thousands of files allowed in root catalogs, default 200 (see also CVMFS_NESTED_KCATALOG_LIMIT and CVMFS_ENFORCE_LIMITS
CVMFS_SNAPSHOT_GROUP	Group name for subset of repositories used with cvmfs_server snapshot -a -g. Added with cvmfs_server add-replica -g.
CVMFS_SPOOL_DIR	Location of the upstream spooler scratch directories; the read-only CernVM-FS moint point and copy-on-write storage reside here.
CVMFS_STATISTICS_DB	Set a custom path for the publisher statistics database
CVMFS_STATS_DB_DAYS_TO_KEEP	Sets the pruning interval for the publisher statistics database (365 by default)
CVMFS_STRATUM0	URL of the master copy (stratum0) of this specific repository.
CVMFS_STRATUM1	URL of the Stratum1 HTTP server for this specific repository.
CVMFS_SYNCFS_LEVEL	Controls how often sync will by called by cvmfs_server operations. Possible levels are ‘none’, ‘default’, ‘cautious’.
CVMFS_UID_MAP	Path of a file for the mapping of file owner user ids.
CVMFS_UNION_DIR	Mount point of the union file system for copy-on-write semantics of CernVM-FS. Here, changes to the repository are performed (see CernVM-FS Repository Creation and Updating).
CVMFS_UNION_FS_TYPE	Defines the union file system to be used for the repository. (only overlayfs is fully supported, aufs has no active support anymore)
CVMFS_UPLOAD_STATS_DB	Publish repository statistics data file to the Stratum 0 /stats location
CVMFS_UPLOAD_STATS_PLOTS	Publish repository statistics plots and webpage to the Stratum 0 /stats location (requires ROOT)
CVMFS_UPSTREAM_STORAGE	Upstream spooler description defining the basic upstream storage type and configuration (see below).
CVMFS_USE_FILE_CHUNKING	Allows backend to split big files into small chunks (true | false)
CVMFS_USER	The user name that owns and manipulates the files inside the repository.
CVMFS_VIRTUAL_DIR	Set to true to enable the hidden, virtual .cvmfs/snapshots directory containing entry points to all named tags.
CVMFS_VOMS_AUTHZ	Membership requirement (e.g. VOMS authentication) to be added into the file catalogs
CVMFS_STATFS_CACHE_TIMEOUT	Caching time of statfs() in seconds (no caching by default). Calling statfs() in high frequency can be expensive.
CVMFS_STATISTICS_DB	SQLite file path to store the statistics. Default is /var/spool/cvmfs/<REPO_NAME>/stats.db .
CVMFS_PRINT_STATISTICS	Set to true to enable statistics printing to the standard output.
X509_CERT_BUNDLE	Bundle file with CA certificates for HTTPS connections (see Large-Scale Data CernVM-FS)
X509_CERT_DIR	Directory file with CA certificates for HTTPS connections, defaults to /etc/grid-security/certificates (see Large-Scale Data CernVM-FS)

Deprecated parameters

Will be removed in future versions.

Parameter	Meaning
CVMFS_GENERATE_LEGACY_BULK_CHUNKS	Deprecated, set to true to enable generation of whole-file objects for large files.
CVMFS_IGNORE_XDIR_HARDLINKS	Deprecated, defaults to true hardlinks are found. Instead automatically break the hardlinks across directories.

Format of CVMFS_UPSTREAM_STORAGE

The format of the CVMFS_UPSTREAM_STORAGE parameter depends on the storage backend. Note that this parameter is initialized by cvmfs_server mkfs resp. cvmfs_server add-replica. The internals of the parameter are only relevant if the configuration is maintained by a configuration management system.

For the local storage backend, the parameter specifies the storage directory (to be served by Apache) and a temporary directory in the form local,<path for temporary files>,<path to storage>, e.g.

CVMFS_UPSTREAM_STORAGE=local,/srv/cvmfs/sw.cvmfs.io/data/txn,/srv/cvmfs/sw.cvmfs.io

For the S3 backend, the parameter specifies a temporary directory and the location of the S3 config file in the form s3,<path for temporary files>,<repository entry URL on the S3 server>@<S3 config file>, e.g.

CVMFS_UPSTREAM_STORAGE=S3,/var/spool/cvmfs/sw.cvmfs.io/tmp,cvmfs/sw.cvmfs.io@/etc/cvmfs/s3.conf

The gateway backend can only be used on a remote publisher (not on a stratum 1). The parameter specifies a temporary directory and the endpoint of the gateway service, e.g.

CVMFS_UPSTREAM_STORAGE=gw,/var/spool/cvmfs/sw.cvmfs.io/tmp,http://cvmfs-gw.cvmfs.io:4929/api/v1

Tiered Cache Parameters

The following parameters are used to configure a tiered cache manager instance.

Parameter	Meaning
CVMFS_CACHE_$name_UPPER	Name of the upper layer cache instance
CVMFS_CACHE_$name_LOWER	Name of the lower layer cache instance
CVMFS_CACHE_LOWER_READONLY	Set to true to avoid populating the lower layer

External Cache Plugin Parameters

The following parameters are used to configure an external cache plugin as a cache manager instance.

Parameter	Meaning
CVMFS_CACHE_$name_CMDLINE	If the client should start the plugin, the executable and command line parameters of the plugin, separated by comma.
CVMFS_CACHE_$name_LOCATOR	The address of the socket used for communication with the plugin.

In-memory Cache Plugin Parameters

The following parameters are interpreted from the configuration file provided to the in-memory cache plugin (see Section Example).

Parameter	Meaning
CVMFS_CACHE_PLUGIN_DEBUGLOG	If set, run CernVM-FS in debug mode and write a verbose log the the specified file.
CVMFS_CACHE_PLUGIN_LOCATOR	The address of the socket used for client communication
CVMFS_CACHE_PLUGIN_SIZE	The amount of RAM in megabyte used by the plugin for caching.