From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [ANNOUNCE] sdparm 0.90 Date: Tue, 19 Apr 2005 10:33:14 +1000 Message-ID: <426451CA.1040301@torque.net> References: <4263B56B.2010905@torque.net> <4263F189.3000700@pobox.com> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from zorg.st.net.au ([203.16.233.9]:38609 "EHLO borg.st.net.au") by vger.kernel.org with ESMTP id S261389AbVDSILu (ORCPT ); Tue, 19 Apr 2005 04:11:50 -0400 In-Reply-To: <4263F189.3000700@pobox.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: linux-scsi@vger.kernel.org Jeff Garzik wrote: > Douglas Gilbert wrote: > >> sdparm is a new command line utility designed to get and set >> SCSI disk parameters (cf hdparm for ATA disks). More generally >> it gets and sets mode page information on SCSI devices or devices >> that use a SCSI command set (e.g. CD/DVD drives (any transport) >> and SCSI tape drives). > > > I'm biased, but I would prefer to use blktool for this sort of thing... Jeff, There is definitely some overlap on the most important parameters for disks (e.g. write caching). blktool covers near end (HBA), transport and device settings. sdparm concentrates on the far end device settings (and in some cases transport settings from the point of view of that device) for devices that use a SCSI command set. sdparm assumes some knowledge of SCSI mode page structure and what facilities are available. Figures and descriptions of mode pages are found in product manuals and SCSI standards (e.g. SPC-3 and SBC-2). Beyond primary settings such as write caching, there are many interesting settings. For example, SCSI disks recovered from (hardware) RAIDs (>= 3) often have the Automatic Read/Write Reallocation bits (ARRE and AWRE) clear. This is not the manufacturer's default. I assume this is to generate medium errors at the first sign of trouble so the parity disk is brought into play. When such a disk is used stand alone, a user would probably want those bits on (and of course they should be using smartmontools or similar to gauge the health of the disk). sdparm can set a mode page back to its manufacturer's default settings. Another example is the tuning mode that Seagate has introduced for its disks (i.e. server or desktop mode). See sdparm.8 for further information. IMO blktool and sdparm complement one another. Doug Gilbert