Xref: utzoo comp.unix.sysv386:2617 comp.unix.questions:27306 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!virtech!cpcahil From: cpcahil@virtech.uucp (Conor P. Cahill) Newsgroups: comp.unix.sysv386,comp.unix.questions Subject: Re: Tuning SYSVR3 (Esix Rev D) (LONG!) Message-ID: <1990Dec02.001311.16727@virtech.uucp> Date: 2 Dec 90 00:13:11 GMT References: <1990Nov20.194829.6977@unixland.uucp> Reply-To: cpcahil@virtech.UUCP (Conor P. Cahill) Organization: Virtual Technologies Inc., Sterling VA Lines: 21 In article karl@ficc.ferranti.com (Karl Lehenbauer) writes: >Anyone have any idea how to reduce these sluggish periods without reducing >the cache size and without reducing the reliability of the file system >with respect to power outages or the performance? You can't. The problem is that the "dirty" blocks sit in the queue for a specified amount of time (unless the block is needed for other uses) before they are forced out by the kernel. The amount of time is controlled by a kernel configuration parameter (NAUTOUP, I think). The problem is that if you increase this variable, you decrease reliability. Even if you set this variable to some high value, it is still possible that at that new time period following a large disk update, the system will slow down momentarily due to many dirty pages that still need to be written out, so you may be in a no-win situation. -- Conor P. Cahill (703)430-9247 Virtual Technologies, Inc., uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160 Sterling, VA 22170