CCEI Storage Appliance

The plankton.che.udel.edu appliance is a home-grown medium-scale storage system. Under the hood it uses a ZOL (ZFS on Linux) filesystem. ZFS has several benefits:

• Per-directory quota control: Any directory (be it a user's storage, content to be visible on the web, whatever) can have a quota (maximum size) or a reservation (guaranteed size).
• Storage pools: The filesystem doesn't live on physical hard disks, it is spread across groups of disks; the filesystem is easily grown by adding more disks.
• Increased integrity: ZFS has advanced data-integrity features like triple-parity RAID and self-healing of silent corruption. Triple-parity means that if three hard disks fail for a given storage pool data will not be lost. Silent corruption is the mangling of bits on the hard disk itself, such that when you later read the data off disk you cannot tell if it is correct or not; ZFS mitigates this using additional checksums and parity data.

ZFS on Linux is an open source project that derives from the Sun (now Oracle) ZFS code that is a part of the Solaris operating system.

With ZOL providing the storage, the appliance needs interfaces through which users (CCEI staff and students) can access it. The following file-sharing mechanisms are currently configured on plankton:

• Samba: Also known as CIFS or SMB, Samba allows you to mount directories on plankton on your Windows/Mac/Linux desktop and work with them as you would any other disk (drag and drop to copy, double-click to open and edit). Samba is NOT a secure file transfer protocol, though, so it is available ONLY when you are on-campus. Even when on-campus, don't use it on any data you consider to be private.
• SFTP/SCP: The Secure FTP and Secure CP programs (part of the SSH client suite) can be used from anywhere on the Internet to connect to plankton and manipulate files.
• NFS: Each CCEI student with an account on squidward as well as on plankton can access his/her plankton directory directly from the head node of squidward.