Hello, I have a customer running an application that opens 24,000 files, and reads from all of them. The application **leaves these files open**. The average file size is 750MB, for a total of 18G of files. Their system has 16G of RAM + 8G of swap. When they run their application on a local drive, the application runs fine. When they run it under Lustre, the application fails at about 10,000 files. I was able to reproduce this on my system with a very simple C program. I first create 1,000 files on /mnt/lustre using dd. My program then allocates 1000 buffers, each 500k big, then reads 500k from the 1000 files. My system has 4G of RAM, and top indicates that this program uses 37% of total memory. If I run the same program with 1,000 files on a local disk, top indicates that it uses 12.1% of RAM. That is 1/3 ! Why is that? Is there anything I can do to change this behavior? I did set max_read_ahead_mb to 1, and max_read_ahead_whole_mb to 0, but that did not seem to help. Thanks. Roger Spellman Staff Engineer Terascala, Inc. 508-588-1501 www.terascala.com http://www.terascala.com/ -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.lustre.org/pipermail/lustre-discuss/attachments/20090306/c46abf02/attachment.html