On Thu, Apr 14, 2011 at 1:52 AM, Sylar Shen <kimulaaa@xxxxxxxxx> wrote: > Hi Sage, > Thanks for your reply. I really appreciated. > I tried what you suggested to set the argument "sync" in /etc/exports. > I also checked "man 5 exports" and it showed that sync means reply to > requests only after the changes have been committed to stable storage. > It didn't mention that the export server won't do the cache task. > However, after I did the experiment, I found that the memory usage of > Ceph-client still went up to maximum value while writing the data > which means Ceph-client did the cache task. > So...are there other possible ways to solve my problem? I don't think the page cache is a "problem," really. It is there to improve performance! However, if you really want to remove pages from the page cache, there is a little-known syscall called fadvise. fadvise(FADV_DONTNEED, ...) will request that the kernel flush a region of the file out of the page cache. I think someone wrote a patch for tar(1) that calls fadvise(FADV_DONTNEED) the files after tar reads them, on the assumption that they would probably not be read again in the near future. Also, there is this: http://code.google.com/p/pagecache-mangagement/ Of course, if you're trying to do performance measurement, I don't think you want to tweak the page cache settings. cheers, Colin -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
