I apologize if this is off-topic, because I'm not sure if /proc/sys/vm/bdflush has anything to do with ext3 performance or not. However, I've been searching around for a while and can't find the answer I need. If somebody could shed some light, I'd really appreciate it. In "Securing and Optimizing Linux: RedHat Edition -A Hands on Guide", the author gives these values to use for bdflush: # echo 100 1200 128 512 15 5000 500 1884 2 > /proc/sys/vm/bdflush I've read the descriptions of what these values mean and think I understand them. However, in another article, a particular reader gave feedback that he thought these numbers were too aggressive because they could leave a lot of data sitting in buffers waiting to be flushed to disk, which could cause data corruption during an unclean shutdown. My question is, if I'm running ext3 in "mode=journal", will the journaling aspects of ext3 protect me even if I tweak the bdflush params like this? Or are these apples and oranges? (and maybe I should just leave the default bdflush params alone...) I have two types of systems I'm configuring, hopefully for heavier load: Single CPU Apache webservers with a single SCSI drive and 512MB RAM, and dual CPU MySQL servers with two SCSI drives and 2GB RAM. Both types are running kernel 2.4.18. Thanks, --jeff
