Shared data areas
In the ideal world, one would adopt some common scalable and manageable file system solution that provides transparent file access (TFA) for all occasions. While TFA requirement is normally a must for home directories, it is often being dropped to give way for less expensive two-tier (disk/tape) custom architectures typical for the large shared data areas in use at the batch farms, and/or to provide other value added features such as extra performance or optimized low level data organization. The following clickable table is an attempt to present a sistematic view of the general picture; we are trying to do our best to provide a sufficent amount of practical information for each of the solutions.
Shared Home Directories
AFS NFS  
TFA
Deployed Base, PB 0.1 0.1
Large Shared Areas for Batch Farms
GPFS LUSTRE XROOTD dCACHE CASTOR HPSS
TFA
HSM Function
NFS Gateway
SRM Access
Deployed Base, PB 1.4 5.5 1.8 10 7.9
Although most of the cited architectures do not include an HSM function, all of them could easily be provided with an automatic data migration to tape and manual data recall to disk. Some of the possible data migration means are mentioned in the table below.
Disk/Tape Migration Means
HPSS TSM ENSTORE STAGER  
Storage Hardware
Last but not least, reliability, performance and cost of each of the data access solutions to a large extent depend on the underlying hardware. We hence tried to make a small up-to-date collection of useful information which could be of help for storage architects.
Hard Disks Solid State Disks Raid Controllers I/O Interconnects
Tape Drives Tape Libraries Disk Servers NAS Appliances