From owner-freebsd-current@FreeBSD.ORG Wed Apr 14 00:08:40 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C0CD6106566B for ; Wed, 14 Apr 2010 00:08:40 +0000 (UTC) (envelope-from jasonjwwilliams@gmail.com) Received: from mail-iw0-f171.google.com (mail-iw0-f171.google.com [209.85.223.171]) by mx1.freebsd.org (Postfix) with ESMTP id 8D21B8FC19 for ; Wed, 14 Apr 2010 00:08:40 +0000 (UTC) Received: by iwn1 with SMTP id 1so2967373iwn.27 for ; Tue, 13 Apr 2010 17:08:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:received:message-id :subject:from:to:content-type; bh=vCcf3nDsKu/JslrlER1ETnimpqgLU25iK9jJ8V2O5cI=; b=KtIF7ePCjqomOeQ7wneXdvAcYEz3R3ckxJ5ZFzongLiKpCmVpoRyQrqnynfInna0dX r6lT5aOVUlm/2yp5JlssIRgZnvF5tsuNQ4jLO1xaFj47cl2EsJRdOfMy924Iz693YwFe 5iFfbh1WZTHm7QUWX6ANuWsLMkxL6z21EHtDk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=AWoijEaWrrHMKZ+x2FLi9nA9qJ6jS7jgopiLiqohe7LKjOkGkSCBJmzcHX+cbLOiE6 0WTM1L6KOZPhyLhc/9W+fhzHYvF8GocHjYile6v4pv0rqjcWaP9pTMOEYmSEo2Zckuig PuswcPNfgWUBeEfkunDBBUxyQ+HSpSnBCZAto= MIME-Version: 1.0 Received: by 10.231.185.144 with HTTP; Tue, 13 Apr 2010 16:39:30 -0700 (PDT) Date: Tue, 13 Apr 2010 17:39:30 -0600 Received: by 10.231.190.204 with SMTP id dj12mr2970191ibb.9.1271201970916; Tue, 13 Apr 2010 16:39:30 -0700 (PDT) Message-ID: From: "Jason J. W. Williams" To: freebsd-current@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: ZFS behavior when device disappears X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Apr 2010 00:08:40 -0000 Hello, Currently, we're an OpenSolaris shop but with the way things are going over at Oracle/Sun we're starting to evaluate our options for keeping ZFS but moving off Solaris. One of my concerns is that FreeBSD is implementing ZFSv14 (ZFS itself is up to v23 I believe). For quite a long time, ZFS under Solaris had a real problem with the following scenario: * Hard drive starts to die * Controller and SCSI subsystem continue to retry an I/O rather than failing fast * Even if the I/O does fail fast ZFS doesn't really notice a spike in I/O failures and continues to use the drive. * Result: I/O on the zpool stalls completely while the I/Os continue to be tried against the drive. This got fixed in later revs of OpenSolaris by enhancements to ZFS and greater integration with the Fault Management Architecture (FMA) of Solaris...lots of I/Os failing on a drive get communicated to ZFS who then offlines the drive out of the pool. My question is, what is the situation in FreeBSD 8 with ZFS if that type of situation occurs? Thank you in advance for your help. -J