Jerome Haltom wrote: > The problem is that during the rsync process the user's machine is > barely usable. The reason is because rsync reads these 2GB files... many > GBs of them. This causes the user's machine to repeatidly trash the page > cache. This really is Linux's fault. It should realize the relative > priority of the two apps and prevent rsync from trashing the cache. But > it doesn't. > > Allowing rsync to specific O_DIRECT would circumvent the page cache > completely. Preventing the cache from being trashed.
On Linux, fadvise(POSIX_FADV_DONTNEED) trailing behind the read/write position is more appropriate for this, I suspect. It also has the advantage of working with all filesystem types on Linux, which O_DIRECT does not. However, there are times when O_DIRECT is useful, and I do use it in a file copying application of mine to control cache memory. -- Jamie -- To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
