# Global HOME¶

Home directories provide a convenient means for a user to have access to files such as dotfiles, source files, input files, configuration files regardless of the platform.

## Usage¶

Refer to your home directory using the environment variable $HOME whenever possible. The absolute path may change, but the value of $HOME will always be correct.

## Quotas¶

Warning

Quota increases in global homes are approved only in extremely unusual circumstances.

Note

See quotas for detailed information about inode, space quotas, and file system purge policies.

## Performance¶

Performance of global homes is optimized for small files and is suitable for compiling and linking executables. Global home directories are not intended for large, streaming I/O. User applications that depend on high-bandwidth for streaming large files should not be run in your $HOME directory. ## Backups¶ All NERSC users should backup important files on a regular basis. Ultimately, it is the user's responsibility to prevent data loss. However, NERSC provides some mechanisms in protecting against data loss. ### Snapshots¶ A snapshot capability is used to provide users a seven-day history of their home directories. Every directory and sub-directory in $HOME contains a .snapshots entry.

• .snapshots is invisible to ls, ls -a, find and similar commands
• Contents are visible through ls -F .snapshots
• Can be browsed normally after cd .snapshots
• Files cannot be created, deleted or edited in snapshots
• Files can only be copied out of a snapshot

### Archive¶

Global homes are backed up to HPSS monthly.

If the snapshot capability does not meet your need contact NERSC Consulting with pathnames and timestamps of the missing data.

Note

Restore requests may take several days to complete.