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diff --git a/doc/xlators/meta.md b/doc/xlators/meta.md new file mode 100644 index 00000000000..da0d62ae3d7 --- /dev/null +++ b/doc/xlators/meta.md @@ -0,0 +1,206 @@ +Meta translator +=============== + +Introduction +------------ + +Meta xlator provides an interface similar to the Linux procfs, for GlusterFS +runtime and configuration. This document lists some useful information about +GlusterFS internals that could be accessed via the meta xlator. This is not +exhaustive at the moment. Contributors are welcome to improve this. + +Note: Meta xlator is loaded automatically in the client graph, ie. in the +mount process' graph. + +### GlusterFS native mount version + +>[root@trantor codebase]# cat $META/version +>{ +> "Package Version": "3.7dev" +>} + +### Listing of some files under the `meta` folder + +>[root@trantor codebase]# mount -t glusterfs trantor:/vol /mnt/fuse +>[root@trantor codebase]# ls $META +>cmdline frames graphs logging mallinfo master measure_latency process_uuid version + +### GlusterFS' process identifier + +>[root@trantor codebase]# cat $META/process_uuid +>trantor-11149-2014/07/25-18:48:50:468259 +> +This identifier appears in connection establishment log messages. +For eg., + +>[2014-07-25 18:48:49.017927] I [server-handshake.c:585:server_setvolume] 0-vol-server: accepted client from trantor-11087-2014/07/25-18:48:48:779656-vol-client-0-0-0 (version: 3.7dev) +> + +### GlusterFS command line + +>[root@trantor codebase]# cat $META/cmdline +>{ +> "Cmdlinestr": "/usr/local/sbin/glusterfs --volfile-server=trantor --volfile-id=/vol /mnt/fuse" +>} + +### GlusterFS volume graph + +The following directory structure reveals the way xlators are stacked in a +graph like fashion. Each (virtual) file under a xlator directory provides +runtime information of that xlator. For eg. 'name' contains the name of the +xlator. + +``` +/mnt/fuse/.meta/graphs/active +|-- meta-autoload +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol +| |-- type +| `-- view +|-- top -> meta-autoload +|-- vol +| |-- history +| |-- meminfo +| |-- name +| |-- options +| | |-- count-fop-hits +| | `-- latency-measurement +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-md-cache +| |-- type +| `-- view +|-- vol-client-0 +| |-- history +| |-- meminfo +| |-- name +| |-- options +| | |-- client-version +| | |-- clnt-lk-version +| | |-- fops-version +| | |-- password +| | |-- ping-timeout +| | |-- process-uuid +| | |-- remote-host +| | |-- remote-subvolume +| | |-- send-gids +| | |-- transport-type +| | |-- username +| | |-- volfile-checksum +| | `-- volfile-key +| |-- private +| |-- profile +| |-- subvolumes +| |-- type +| `-- view +|-- vol-client-1 +| |-- history +| |-- meminfo +| |-- name +| |-- options +| | |-- client-version +| | |-- clnt-lk-version +| | |-- fops-version +| | |-- password +| | |-- ping-timeout +| | |-- process-uuid +| | |-- remote-host +| | |-- remote-subvolume +| | |-- send-gids +| | |-- transport-type +| | |-- username +| | |-- volfile-checksum +| | `-- volfile-key +| |-- private +| |-- profile +| |-- subvolumes +| |-- type +| `-- view +|-- vol-dht +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | |-- 0 -> ../../vol-client-0 +| | `-- 1 -> ../../vol-client-1 +| |-- type +| `-- view +|-- volfile +|-- vol-io-cache +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-read-ahead +| |-- type +| `-- view +|-- vol-md-cache +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-open-behind +| |-- type +| `-- view +|-- vol-open-behind +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-quick-read +| |-- type +| `-- view +|-- vol-quick-read +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-io-cache +| |-- type +| `-- view +|-- vol-read-ahead +| |-- history +| |-- meminfo +| |-- name +| |-- options +| |-- private +| |-- profile +| |-- subvolumes +| | `-- 0 -> ../../vol-write-behind +| |-- type +| `-- view +`-- vol-write-behind + |-- history + |-- meminfo + |-- name + |-- options + |-- private + |-- profile + |-- subvolumes + | `-- 0 -> ../../vol-dht + |-- type + `-- view + +``` |