On Nov 23, 2010, at 12:15 AM, Simon Wilkinson wrote: > > On 22 Nov 2010, at 23:06, Achim Gsell wrote: >> >> 3.) But if I first open 8 files and - after this is done - start writing to >> these files sequentially, the problem occurs. The difference to 1.) and 2.) >> is, that I have these 8 open files while the test is running. This simulates >> the "putc-test" of bonnie++ more or less: > > AFS is a write-on-close filesystem, so holding all of these files open means > that it is trying really hard not to flush any data back to the fileserver. > However, at some point the cache fills, and it has to start writing data > back. In 1.4, we make some really bad choices about which data to write back, > and so we end up thrashing the cache. With Marc Dionne's work in 1.5, we at > least have the ability to make better choices, but nobody has really looked > in detail at what happens when the cache fills, as the best solution is to > avoid it happening in the first place!
Sounds reasonable. But I have the same problem with a 9GB disk-cache, a 1GB disk-cache, 1GB mem-cache and a 256kB mem-cache: I can write 6 GB pretty fast then performance drops to < 3MB/s ... So long Achim _______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
