DCache summary¶DCache is a high throughput, medium latency file system, supporting several protocols
- ftp ( password, kerberized, grid )
- nfs 4.1
Files cannot be modified or appended.
Backed up by tape via Enstore by default.
SFA (Small File Aggregation) allows efficient tape storage of small files.
/pnfs/*/scratch areas are not backed up to tape, for volatile files.
Clients connect to doors which redirect data to the pools hosting the files.
Pools self-regulate activity to acceptable levels, when properly adjusted.
Directory operations require access to a backend database.
- ls about 100/second
- ls -l about 10/second
- ls about 5000/second
- ls -l about 2000/second
- readWritePools - 17 hosts
- PublicScratch - 9 hosts
What is the network link capacity between DCache and GPGrid ?