proxy.flexfs

Note

Proxy groups are an Enterprise-only feature.

proxy.flexfs is a CDN-like block caching server that sits between mount clients and object storage. Multiple proxy servers form a proxy group. Mount clients distribute blocks across group members using rendezvous hashing and select groups based on RTT-based latency measurements.

Subcommands

Subcommand	Description
deinit creds	Remove the credentials file
deinit systemd	Remove the systemd service unit
init creds	Initialize the credentials file
init systemd	Create and enable a systemd service unit
license	Print license information
start	Start the proxy server
version	Print the build version

Usage

proxy.flexfs start [flags]

Persistent Flags

Flag	Type	Default	Description
--credsFile	string	~/.flexfs/proxy/creds	Credentials file path

Start Flags

Flag	Type	Default	Description	Visibility
--bindAddr	string	0.0.0.0:443	Address and port to bind	Public
--blockPass	string		Block storage password (overrides creds file)	Internal
--blockUser	string		Block storage username (overrides creds file)	Internal
--bufferSize	uint32	1048576	I/O buffer size	Internal
--dbFolder	string	~/.flexfs/proxy/data	Database folder path	Public
--dbMemCapacity	string	10%	Database memory cache capacity (e.g. 5%, 64M)	Internal
--diskFolder	string	/cache	On-disk block cache folder path	Public
--diskQuota	string	90%	On-disk block cache capacity (e.g. 5%, 64M)	Public
--maxBops	uint32	0 (auto)	Maximum number of active parallel block operations	Internal
--minDiskAvail	string	1G	Minimum available space required on the database folder filesystem (e.g. 2%, 512M; 0 disables)	Internal
--noSSL	bool	false	Disable SSL for the REST API	Public
--noWriteback	bool	false	Disable writeback to persistent storage	Internal
--pprof	bool	false	Enable pprof profiler	Internal
--pprofPort	int	6064	Pprof server port	Internal
--sse	bool	false	Enable S3 server-side encryption (AES256)	Internal
--sslCert	string	~/.flexfs/ssl/cert	SSL certificate file path	Public
--sslKey	string	~/.flexfs/ssl/key	SSL private key file path	Public
--sync	bool	false	Fsync dirty block writes for full crash durability	Public
--verbose, -v	bool	false	Enable verbose logging	Public
--writebackActive	uint32	0 (auto)	Maximum number of active parallel writeback operations	Internal
--writebackDelay	uint32	0	Milliseconds each writeback should sleep	Internal

Auto-computed Defaults

When --maxBops is left at 0, the proxy computes a default based on the host’s CPU count. --writebackActive defaults to the computed --maxBops value.

Low disk space protection

The proxy tracks its cached blocks in a database under --dbFolder, which cannot be written safely on a filesystem that has run out of space. The server therefore guards that filesystem:

• On startup, it refuses to start if the available space is already below --minDiskAvail.
• While running, it re-checks every minute and shuts down gracefully as soon as available space drops below --minDiskAvail. Both events are logged, naming the folder and the space available.

The block cache under --diskFolder is bounded separately by --diskQuota, so this guard is about the database folder; when both live on the same filesystem, it covers them together. Watch flexfs_proxy_db_folder_disk_available_bytes to catch this well before it happens; see Alerting. Setting --minDiskAvail to 0 disables both checks.

Init Creds

proxy.flexfs init creds [flags]

Initializes a credentials file for the proxy server with block storage credentials.

Flag	Type	Default	Description
--blockPass	string	""	Block storage password
--blockUser	string	""	Block storage username
--force	bool	false	Overwrite existing creds file

Init Systemd

sudo proxy.flexfs init systemd [flags]

Creates and enables a systemd service unit (flexfs-proxy.service) for the proxy server. Requires root.

Flag	Type	Default	Description
--force	bool	false	Overwrite existing systemd unit file
--now	bool	false	Start the service immediately after enabling
--startFlags	string	""	Additional flags to pass to the start command

Deinit Creds

proxy.flexfs deinit creds [flags]

Removes the credentials file for the proxy server. If the credentials file is referenced by a systemd unit, the command refuses unless --force is passed, in which case it removes the references too.

Flag	Type	Default	Description
--force	bool	false	Remove creds even if referenced by systemd (removes references too)

Deinit Systemd

sudo proxy.flexfs deinit systemd

Removes the systemd service unit (flexfs-proxy.service) for the proxy server. Requires root.