On Tue, Apr 13, 2010 at 12:23:23AM -0700, Bill Broadley wrote: > On 03/31/2010 05:12 PM, Alex Mandel wrote: > > I'm looking for some references and tips on how to tune a server > > specifically for serving large files over the internet. ie 4 GB iso > > files. I'm talking software config tweaks here. > > How many 4GB ISO files are there? How many simultaneous files? > Clients? How fast is the uplink to er, umm, wherever the clients are > (on the internet)? > > > The system is using a RAID with striping, the filesystem is XFS (some > > tuning there maybe?) > > Your enemy is random access, I wouldn't expect XFS, ext2/3/4, jfs, or > any of the many other alternatives to make much difference. > > > and will be running Apache2.2 all on a Debian > > Stable install if that helps. It's got 2 2.5ghz cores and 8GB of ram > > (those can be adjusted since it's actually a kvm virtual machine). > > Well your enemy is random access. To keep things simple lets just > assume a single disk. If you have one download and relatively current > hardware you should be able to manage around 80-90MB/sec (assuming your > network can keep up). > > What gets ugly is if you have 2 or more clients accessing 2 or more > files. Suddenly it becomes very very important to intelligently handle > your I/O. Say you have 4 clients, reading 4 ISO files, and a relatively > stupid/straight forward I/O system. Say you read 4KB from each file (in > user space), then do a send.
That's like operating a disk in PIO mode. I would think something that can leverage the DMA controller better would avoid thrashing. Perhaps there is a way to tell apache to use memory cache and dump readaheads into memory. Linux should be able to handle this fine. I was looking to see if there is a config on this, but I can't find one at the moment. I was looking at this cache page. http://httpd.apache.org/docs/2.2/mod/mod_mem_cache.html I imagine someone else has encountered this problem before. brian -- Brian Lavender http://www.brie.com/brian/ "Those that fail to learn from history, are doomed to repeat it." - Winston Churchill _______________________________________________ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech