start:fs_dm:archiving:irods:details

# Storage Locations

iRODS works based a kind of a virtual file system, with its own lingo:

• directories are called collections, they may contain further subcollections
• files are (data objects).

iRODS uses so called 'Resources' to archive the collections and data objects. The resources are organized hierarchically. The root is a replication resource, where other resources are added as children. Currently there is a compound resource consisting itself of a cache (unix filesystem) and a universal mass storage system (here: TSM) as archive. The cache has a size of 8TB, once it is fills up, the oldest data objects will be deleted on the cache. If required, they will be fetched back from the archive.

replResc:replication
├── cephfsResc:unixfilesystem
└── compResc:compound
├── netappResc:unixfilesystem
└── tsmResc:univmss

# Transfer Speeds

Here we show some transfer speed benchmarks:

This explains why a directory, resp. collection, consisting of many small files, should be compressed. iRODS works best for files > 5GB.

# Supplied iRODS Configuration

Every user has a hidden directory ${HOME}/.irods with the file irods_environment.json our the HPC Systems home directory containing the connection information for the iRODS archive. Below you see the information template for irods_environment.json. Do not edit this file. { "irods_client_server_negotiation": "request_server_negotiation", "irods_client_server_policy": "CS_NEG_REQUIRE", "irods_authentication_scheme": "KRB", "irods_host": "irods.zdv.uni-mainz.de", "irods_port": 1247, "irods_user_name": "<$USER>",
"irods_zone_name": "zdv",
"irods_encryption_key_size": 32,
"irods_encryption_salt_size": 8,
"irods_encryption_num_hash_rounds": 16,
"irods_encryption_algorithm": "AES-256-CBC"
}

Please do not use iinit, it will not work and change your ${HOME}/.irods/irods_environment.json file. In case it happened, remove the directory ${HOME}/.irods and log in again, it will be restored upon login.

#### Security Risk

If you initiate the command iinit it might happen that an additional file .irodsA is also in the directory \${HOME}/.irods . Please remove this file! It contains your password in a decryptable form.
• start/fs_dm/archiving/irods/details.txt