GeoTags

In a geographically distributed storage system it is important to tag each storage server with a geographical location. You should group servers into LAN groups e.g. all servers which are close in term of network latency shared a GeoTag. GeoTags are just arbitrary strings (for the time being). Each FST defines in /etc/sysconfig/eos a GeoTag:

Storage Node Tagging

# The EOS host geo location tag used to sort hosts into geographical (rack) locations
export EOS_GEOTAG="CERN::513::1"

Warning

Each portion of the GeoTag string must be delimited by ”::” and have a maximun length of 8 characters

Client Tagging

To optimise the network path it is not enough to tag only the storage server. EOS allows you to define IP prefixes to match a client to a certain location. This is done via the vid command:

eos vid -h
...
vid set geotag <IP-prefix> <geotag>  : add to all IP's matching the prefix <prefix> the geo location tag <geotag>
                                       N.B. specify the default assumption via 'vid set geotag default <default-tag>'

As an example we could define the default location to be CERN:

eos vid set geotag default CERN

While we want to assign all clients with 111.222.x.x. to CANADA:

eos vid set 111.122. CANADA