From a co-worker. Anyone know what might have changed this between 2.6.18 and 2.6.19 when the issue first appeared? -- Dave Lloyd Product Support Engineer, Exegy, Inc. +1.314.450.5342 dlloyd@exegy.com -------- Original Message -------- Subject: [Fwd: xfs write speed regression 2.6.18.1 to 2.6.19.1] Date: Fri, 05 Jan 2007 16:16:11 -0600 From: Mr. Berkley Shands To: Dave Lloyd The short summary is under 2.6.18.* xfs is able to maintain a write rate of > 900MB/Sec for the first TB of data. Peak is ~256MB/Sec per raid X 4 raids. Under 2.6.19.1 this rate drops to ~220MB/Sec. and the allocations are no longer smooth starting at the outside edges. under 2.6.20-rc3 the speeds have gone back up some, but they are 10% slower than 2.6.18. and the allocations, as shown by the sequential writes (attached) are random. If I went all the way out to the inside tracks, you would be at about 490MB/Sec. Something changed. 2.6.19 was unstable, with XFS panics on a regular basis. 2.6.19.1 has not had an error yet.. (knock head on wall repeatedly). berkley -- //E. F. Berkley Shands, MSc// **Exegy Inc.** 3668 S. Geyer Road, Suite 300 St. Louis, MO 63127 Direct: (314) 450-5348 Cell: (314) 303-2546 Office: (314) 450-5353 Fax: (314) 450-5354 This e-mail and any documents accompanying it may contain legally privileged and/or confidential information belonging to Exegy, Inc. Such information may be protected from disclosure by law. The information is intended for use by only the addressee. If you are not the intended recipient, you are hereby notified that any disclosure or use of the information is strictly prohibited. If you have received this e-mail in error, please immediately contact the sender by e-mail or phone regarding instructions for return or destruction and do not use or disclose the content to others.