FileFamilies

Introduction

A file family is a set of files which are grouped exclusively on the same set of tapes. File families are used to indicate groups of files that may be treated differently during data-handling operations. This might include tape library location, groupings for migration, deletion, duplication, copy offsite, groupings for access priority or dCache location or lifetime on disk. For example, we expect to group raw data, reconstructed data, and simulations on different sets of tapes for data security and operational efficiency.

List

Here are the standard mu2e file families. Knowledge about these file families is built into the production and upload procedures so the typical users does not need to understand this in any detail.

• phy-raw Raw data from the central or subdetector DAQ system. Data written here is copied onto two different tapes.
• phy-rec Reconstructed beam/cosmic data
• phy-ntd Production non-art format ntuples of reconstructed beam/cosmic data
• phy-sim Monte Carlo simulated or reconstructed art files. These are official collaboration samples only, originated, produced, validated, and documented by physics groups intended for long-term use by many collaborators. Examples are the TDR and CD3 samples. The username associated with the files will be the production username "mu2e".
• phy-nts non-art format ntuples of phy-sim
• phy-etc configuration files, tarballs of log files, backups, and other files
• usr-dat User data-based reconstruction or ntuples
• usr-sim Monte Carlo simulated or reconstructed art files. These samples are produced by one or a few individuals for use in their personal studies. They are probably for short-term use, not documented publically, and not used by many collaborators. The username associated with these files will be the person most likely to understand how they were created and how they should be used if questions come up a year or two later - the intellectual owner of the data.
• usr-nts Non-art format ntuples of usr-sim
• usr-etc Other user-created tarballs of log files, backups
• tst-cos (to be deprecated, use phy-raw) Testbeam and cosmic data created before detector commissioning. This would include raw data formats as well as various possible derived formats and tarballs. Data written here are stored on tape with two automatic copies of each file.

When uploading files, you must follow the upload recipes. The scripts will steer your data to the correct file family based on the file name, see the next section.

Currently (9/2021) all families have a width of 2, except usr-nts which has a width of 3. The width is how many tape drives can be used in parallel to write file to this family.

Determining file family

In the file name convention the first two fields are the data_tier (a logical grouping based on physics contents) and the user name (either "mu2e" for collaboration files, or a person's username for everything else). We have decided by convention that these two fields will determine which file family a file will be steered to. This is a useful feature which allows the file family to be determined automatically. The table below reflects the coded convention. The case of real detector data is likely to be more complex, and will be decided when needed.

data_tier	user mu2e	other users
raw	phy-raw	phy-raw
rec	phy-rec	usr-dat
ntd	phy-ntd	usr-dat
ext	?	usr-dat
rex	?	usr-dat
xnt	?	usr-dat
cnf	phy-etc	usr-etc
sim	phy-sim	usr-sim
dts	phy-sim	usr-sim
mix	phy-sim	usr-sim
dig	phy-sim	usr-sim
mcs	phy-sim	usr-sim
nts	phy-nts	usr-nts
log	phy-etc	usr-etc
bck	phy-etc	usr-etc
etc	phy-etc	usr-etc
job	N/A	N/A

A default family

The computing division has created a default file family for Mu2e called sfu_archive. This would contain files uploaded using the fife_utils tools. These tools are intended for convenience of the user who just wants to backup an area to tape quickly. The tools do not understand the Mu2e location convention, filename convention, or sam metadata standards, so in general we do not recommend using these tools.