WMCS instances have some extra disk space which is not mounted by default. It can be mounted on `/srv` using role::labs::lvm::srv. There is a legacy class role::labs::lvm::mnt (which mount it on `/mnt`) which is deprecated and should be removed entirely.
Continuous integration was among the early adopters of /mnt. They all got migrated to /srv via T146381.
Labs instances should be switched to role::labs::lvm::srv @hashar wrote a migration guide on https://gerrit.wikimedia.org/r/#/c/330412/ :
* switch from role::labs::lvm::mnt to role::labs::lvm::srv
* run puppet
* kill anything that might be using /mnt (lsof /mnt)
* manually umount /mnt
* ensure /srv is mounted
* **VERIFY /mnt is no more refered to in /etc/fstab**
** failure to do so would cause the instance to be deadlocked on the next reboot
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Instances https://tools.wmflabs.org/openstack-browser/puppetclass/role::labs::lvm::mnt
As of October 20 2017:
Project: deployment-prep #beta-cluster-infrastructure
* deployment-logstash2.deployment-prep.eqiad.wmflabs
Project: tools #paws
* tools-paws-*
Project: wikidata-ldf #wikidata
* wikidata-ldf.wikidata-ldf.eqiad.wmflabs