Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!agate!helios.ee.lbl.gov!ace.ee.lbl.gov!leres From: leres@ace.ee.lbl.gov (Craig Leres) Newsgroups: comp.unix.wizards Subject: Re: Raw disk I/O Message-ID: <5071@helios.ee.lbl.gov> Date: 14 Mar 90 06:58:26 GMT References: Sender: usenet@helios.ee.lbl.gov Followup-To: comp.unix.wizards Organization: Lawrence Berkeley Laboratory, Berkeley Lines: 22 X-Local-Date: 13 Mar 90 22:58:26 PST (Sorry to jump into this so late but it seems like I never have time to read news.) Folks interested in raw disk I/O will also be interested in the little disk bench mark package we've thrown together. Eventually, I'd like to it to include a complete tutorial on How To Tune Your Filesystem; for now the (limited) documentation really only deals with how to measure raw disk speeds. The package is easy to use; the primary part is the "disktest" script which does raw reads at block sizes ranging from 4k to 128k. There's a simple line fitting program that allows you to munch "disktest" runs down to the throughput (in KB/sec) and fixed overhead (in ms) numbers. For example, I've measured 2094.07 KB/sec, 1.49 ms on my Sun 3/180 which runs SunOS 3.5 and has Fujitsu M2344's on an Interphase 4400 controller. There are also some scripts for use with xgraph. The disktest package is available via anonymous ftp from the host ftp.ee.lbl.gov (128.3.254.68) in the file disktest.shar.Z. As usual, use binary mode for best results. Craig