From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: SCSI target and IO-throttling Date: Wed, 15 Mar 2006 20:15:21 +0300 Message-ID: <44184BA9.90202@vlnb.net> References: <440EF9AC.7070903@vlnb.net> <440F1920.1050608@vlnb.net> <43998989-7BD3-4F3F-A10A-17385D63411E@egenera.com> <441075D4.6010109@vlnb.net> <80454C34-75B9-409B-A454-B8AB0DB1AF4D@egenera.com> <4411C99C.9040200@vlnb.net> <44172D88.6070201@torque.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from out-relay-02.infobox.ru ([195.208.234.171]:48574 "EHLO out-relay-02.infobox.ru") by vger.kernel.org with ESMTP id S1750738AbWCORPf (ORCPT ); Wed, 15 Mar 2006 12:15:35 -0500 In-Reply-To: <44172D88.6070201@torque.net> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: dougg@torque.net Cc: Steve Byan , Bryan Henderson , linux-scsi@vger.kernel.org Douglas Gilbert wrote: > Vladislav Bolkhovitin wrote: > >>Steve Byan wrote: > > > > >>BTW, do you have any statistic how many modern SCSI disks support those >>features (ORDERED, ACA, UA_INTLCK_CTL, etc)? Few years ago none of >>available for us SCSI hardware, including tape libraries, supported ACA. >>It was not very modern for that time, though > > > Vlad, > Here is part of the control mode page from a > recent SCSI disk (Cheetah 15k.4) : > > # sdparm -p co /dev/sdb -ll > /dev/sdb: SEAGATE ST336754SS 0003 > Direct access device specific parameters: WP=0 DPOFUA=1 > Control mode page [PS=1]: > TST 0 [cha: n, def: 0, sav: 0] Task set type > 0: lu maintains one task set for all I_T nexuses > 1: lu maintains separate task sets for each I_T nexus > TMF_ONLY 0 [cha: n, def: 0, sav: 0] Task management functions only > D_SENSE 0 [cha: n, def: 0, sav: 0] Descriptor format sense data > GLTSD 0 [cha: y, def: 1, sav: 0] Global logging target save disable > RLEC 0 [cha: y, def: 0, sav: 0] Report log exception condition > QAM 0 [cha: y, def: 0, sav: 0] Queue algorithm modifier > 0: restricted re-ordering; 1: unrestricted > QERR 0 [cha: n, def: 0, sav: 0] Queue error management > 0: only affected task gets CC; 1: affected tasks aborted > 3: affected tasks aborted on same I_T nexus > RAC 0 [cha: n, def: 0, sav: 0] Report a check > UA_INTLCK 0 [cha: n, def: 0, sav: 0] Unit attention interlocks control > 0: unit attention cleared with check condition status > 2: unit attention not cleared with check condition status > 3: as 2 plus ua on busy, task set full or reservation conflict > SWP 0 [cha: n, def: 0, sav: 0] Software write protect > ATO 0 [cha: n, def: 0, sav: 0] Application tag owner > TAS 0 [cha: n, def: 0, sav: 0] Task aborted status > 0: tasks aborted without response to app client > 1: any other I_T nexuses receive task aborted > > So it doesn't support UA_INTLCK ("cha: n" implies the user > cannot change that value). QAM can be changed to allow > unrestricted re-ordering (of task with the SIMPLE task > attribute). > > The NormACA bit in the standard INQUIRY response is 0 so > it doesn't support ACA either. Thanks! This is exactly what we've seen in the our small investigation. Perhaps, those features are really not needed, if nobody still use them. Vlad