There are several independent Lustre file systems available, they are automounted at /lustre/, e.g. /lustre/fs17 on all farm and pax cluster machines, on transfer and on the workgroup servers. They are not mounted on the desktops. You can use sshfs to access Lustre on a Linux desktop.
You can use the Lustre file system assigned to your group to store your data. Please be aware that there is no backup, use Lustre as a fast scratch space. Don't store many small files on Lustre, it will slow down the file system and fill up the metadata server. As a rule of thumb, Lustre was optimized for files with a size of at least 1 MB, the bigger the file the better.
There are no quotas set for individual users, but there is a quota for the UNIX group. Use a command like lfs quota /lustre/fs16/ to display the quota limit and your used space in kbytes.
Access control lists are enabled most Lustre file systems. Lustre ACL support is based on the POSIX draft and are different from AFS ACLs. You can use the tools setfacl and getfacl, just like on a local ext4 file system.
The machine transfer.zeuthen.desy.de has Lustre mounted and is reachable over SSH. Contact UCO-ZN for Grid access or for sharing with external users over the web.