File storage on Local Disks


WARNING - FILES left on the LOCAL drive of any Client machine are NOT backed up and will not be recovered if lost or deleted.

Certain types of service to the computer (like installing a New OS) may wipe files on the local drives (as will certain Viruses/Trojans/Worms).



Some Definitions:

Local Drive - any drive (or storage device) physically attached to your machine that is not easily removed.
You are responsible for backing up any data you keep on Local Drives.

Removable Storage - any drive or storage device physically attached to your machine that can be easily removed without turning off the machine (example: USB Flash Drives).
You are responsible for backing up any data you keep on Removable Storage.

Enet Storage - This is storage space on Enet Maintained and backed up servers.
Examples for Enet Managed Windows/Mac Machines: Your Home Directory (H:), GHOME(G:), RHOME(R:), PROJECT(U:)
Examples for Enet Managed Linux Machines: All folders under /h, /g, and /my
For more information on how to use network storage see: Connecting to Enet Shared folders

Backup - A copy of data that is physically kept in another location.
a backup must be kept Where it is not prone to destructive incidents that may affect the primary data (like fires, floods, explosions, Magnetic distubances, etc).
Also a backup must be detached from the machine that has the primary data (so NO operation on the primary machine can affect the backup).
While it is attached to the machine it is NOT a backup (the machine could destroy the entire copy under the control of a Trojan/Worm/Virus or even due to a power surge).
A backup is ONLY a backup while the primary data exists (otherwise it becomes the primary data and there is no backup).

Archive - An unchangeable Complete Copy with 2 backup copies (3 OR MORE total copies).
Usually this is kept on Write ONCE optical storage (CDR, DVDR, BlueRay-R - NOT on eraseable media).
Generally you don't have an archive unless you have 2 copies (and the original - total 3), each kept in different secure locations (so there is no risk of losing data).


Using "/scratch/${USER}" and "/scratch2/${USER}" on Enet Managed Machines

Warning: Enet may remove any files under "/scratch" and "/scratch2" that are over 10 days old to make space for other users, so make sure you don't leave anything there that can't be re-created.


Enet Managed Windows Machines:

Enet discourages this on windows, so you will have to ask Enet to make a folder for you.
The location would be either "C:\SCRATCH\%username%" or "D:\SCRATCH\%username%"
On some machines it may be a PUBLIC folder: "C:\SCRATCH\TEMP"
Enet will NOT make these folders on Public Lab Windows Machines.

Enet Managed Linux Machines:

On Most machines, you can put your temporary stuff in "/scratch/${USER}" (you should make a personal folder under "/scratch" with your username for your use - DO NOT put files directly in "/scratch"). This directory is not automatically emptied on reboot (Please remove your stuff when you are done).
You should make a "/scratch/${USER}" or "/scratch2/${USER}" folder for yourself

To create a "/scratch/${USER}" space for yourself run these two commands in order (verbatim - exactly as you see them below):
	md "/scratch/${USER}"
	chmod go= "/scratch/${USER}"

You may use "/scratch/${USER}" and/or "/scratch2/${USER}" on Enet managed machines for the TEMPORARY storage of files - (if you have write access to these folders).

"/scratch/${USER}" is LOCAL to the machine and you will be able to access files there at a much higher speed than files in your home directory (plus the space is only limited by the space available on /scratch - not by quotas) - so this is a good place to have background jobs write and read data (to speed them up).

When running programs that require the manipulation of large files (good examples are ANSYS and matlab) , it is best to run the jobs from /scratch/${USER} instead of your home directory. /scratch/${USER} is located on the local drive, so that when the program is loading the files it does not have to move the data over the network.

The result is that your calculation will run faster (since large amounts of data are not being passed over the network), the machine will be less burdened by the job, and the network response will be much better. Everyone benefits.

Note that when your job is finished, you must move the results and any other files to your home directory (or some other backed up location), since /scratch/${USER} is only meant for temporary data storage (although we will tend to leave them alone for 10 days).


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