0. Xrootd proxy cache server at AGLT2.

1. Under heavy load, the xrootd proxy cache sometimes can't send data back to some clients (broken pipe/send failure). Currently focus on checking OS/networking setting. Increase "txqueuelen" in NIC (ens2) from 1000 to 20000 - doesn't help. Reviewing other parameters.

2. Question about uncommitted data in memory when a client close connection. Prefer to commit the data to disk to increase proxy efficiency but it is not always possible under heavy load. Will discard those data.

3. Occasional lose of file descriptors (including TCP). 22 files so far in the last two days of stress test (out of 224k). _May_ due to a linux kernel semaphore bug which is fixed in the latest kernel. Need to confirm.

4. After 1. is understood, will enter long period of stress test to check stability, memory usage, file/TCP descriptors, and networking.

5. Packaging as a product.