From owner-freebsd-scsi@FreeBSD.ORG Wed Jan 26 23:07:11 2011 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D62641065672 for ; Wed, 26 Jan 2011 23:07:11 +0000 (UTC) (envelope-from david.tidey@tidey.com) Received: from mail-qy0-f182.google.com (mail-qy0-f182.google.com [209.85.216.182]) by mx1.freebsd.org (Postfix) with ESMTP id 98C928FC16 for ; Wed, 26 Jan 2011 23:07:11 +0000 (UTC) Received: by qyk36 with SMTP id 36so1468206qyk.13 for ; Wed, 26 Jan 2011 15:07:11 -0800 (PST) MIME-Version: 1.0 Received: by 10.229.229.68 with SMTP id jh4mr852289qcb.103.1296081339543; Wed, 26 Jan 2011 14:35:39 -0800 (PST) Received: by 10.229.222.141 with HTTP; Wed, 26 Jan 2011 14:35:39 -0800 (PST) Date: Wed, 26 Jan 2011 22:35:39 +0000 Message-ID: From: David Tidey To: freebsd-scsi@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: istgt performance issue when copying large files (1G plus) X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jan 2011 23:07:11 -0000 Hello, I am using FreeBSD 8.2 with the very latest istgt version 20110103. I am using istgt to expose a zfs volume to a windows client. When running a disk benchmark which writes 10 files of around 40mb each performance is 60-70Mb/sec. When I copy a video file over over 1G performance starts off fast - 60Mb/sec plus. After copying a couple of 100Mb performance starts to drop to less than 10Mb/sec. Exposing the same disks using samba gives performance of 40-50Mb/sec with no drop off problems I therefore am assuming this is an istgt problem Any views on how to diagnose this? David