eRSA data area

Information about the changes.
The eRSA data area has been migrated to a new storage area which has allowed us to significantly increase the available storage space.
This affects these directories, /data/users, /data/grid, /data/bio.

Here is a list of the improvements made to the eRSA data area.

* The total disk storage has been increased from 2.8TB to 4.7TB.
* It is now connected to our DMF heirachical storage system. This allows us to add tape to the storage pool to function along side the disk.
* There is currently 6TB of tape available to the eRSA data area.
* It is easy to expand the storage by adding additional tapes.

In total there is now 10.7TB of available storage for eRSA data.

Why use DMF to migrate data from disk to tape?
Spinning disks are expensive to buy, run and maintain. They use up large amounts of electricity and cooling to stay online.
Tapes are much cheaper to buy, only use energy when being read or written to, and are generally more environmentally friendly. Tapes are also designed to archive data for 25 years, where disks in general are rated to last 5 years.

How does this new tape area work?
DMF migrates data seemlessly between hard disk arrays and tapes.
Data managed by DMF has three states:

REG - Regular, only on disk
DUL - Dual state, is on tape and disk.
OFL - Offline, data is only on tape.

DMF automatically migrates data when it has not been modified for a period of 2 or more months.
Files you use every day, once a week, or once a month, will not get migrated to tape and will always be available on disk. for quick access.

Whats the difference between accessing tape and disk?
Disk access occurs in a matter of milliseconds. Tape access takes roughly 15 seconds on our tape silo.

When my data is migrated to tape, does it disappear out of my directory!?
No. You will still see the file on the disk as though it was a real file. It will however actually live on tape.

How long will I have to wait for my file if it is on tape?
Generally, when a request is made to a file that is offline on tape, you can expect to wait roughly 25 seconds for the file to come back to disk.

I'm having trouble accessing my files, what do I do?
Please contact the service desk.