From: Kurt Chan , HP To: FC, SCSI Reflectors Subj: 7/95 FC-AL Direct Attach Disk Adhoc Minutes Date: 7/11/95 FC-AL Direct Attach Disk Adhoc Meeting Minutes Colorado Springs, CO 7/10/95 Dal Allan ENDL dal.allan@mcimail.com Charles Binford Symbios Logic charles.binford@symbios.com Kurt Chan HP Roseville kc@core.rose.hp.com Mike Chenery Fujutsu mchenery@fcpa.fujitsu.com Jim Coomes Seagate jim_coomes@notes.seagate.com Tom Coughlan Digital coughlan@star.enet.dec.com Edward Fong Amdahl edward_fong@spg.amdahl.com Giles Frazier IBM gfrazier@ausvm6.vnet.ibm.com Gene Freeman Symbios Logic gene.freeman@symbios.com Ed Gardner Quantum gardner@acm.org Doug Hagerman Digital hagerman@starch.enet.dec.com Norm Harris Adaptec nharris@eng.adaptec.com Bill Hutchison HP hutch@boi.hp.com Skip Jones Qlogic sk_jones@qlc.com Jean Kodama QLogic j_kodama@qlc.com Mark Lewis Digital lewis@ssdevo.enet.dec.com Gene Milligan Seagate gene_milligan@notes.seagate.com Charles Monia Digital monia@shr.dec.com Al Pease Buslogic alp@buslogic.com Jim Pherson Digital pherson@ssdevo.enet.dec.com Lansing Sloan LLNL ljsloan@llnl.gov Bob Snively Sun bob.snively@sun.com Arlan Stone Unisys arlan.stone@mv.unisys.com Horst Truestedt IBM truested@vnet.ibm.com Michael Walker Digital walker@peaks.enet.dec.com Stewart Wyatt HP DMD stewart@hpbs3928.boi.hp.com Anthony Yang Hitachi yang_a@halsp.hitachi.com 1. SCHEDULE There are no future FC-AL direct attach disk adhoc meetings scheduled. The next two FC-AL2 meetings will be held Friday mornings of X3T11 weeks: Fri 8/11, 830am Tarrytown, NY Fri 10/6, 830am Toronto The Monday slot during X3T10 weeks will no longer be used for either profile or FC-AL meetings. 2. DOCUMENT LOGISTICS Revision 1.90 of the Direct Attach profile was distributed, and revision 2.00 will be the version forwarded to X3T11 as a Technical Report (TR). The postscript for the profile is available via anonymous ftp on ftp.symbios.com unden pub/standards/io/fc/prv_*.ps. Dal distributed copies of an X3T11 project proposal for creating the TR. Any future discussions kegarding the profile will take place on the disk_attach reflector (disk_attach@dt.wdc.com). To subscribe or unsubscribe, send email to majordomo@dt.wdc.com with a blank subject line and one of the following text lines: subscribe disk_attach your_email_address unsubscribe disk_attach your_email_address When posting to the reflector, please include a header which includes a "From:" and "To: disk_attach" field so those of us who subscribe to multiple reflectors know which reflector the posting is associated with. 3. TIMERS AND TIMEOUTS Version 1.90 reevaluates the timers needed for interoperability on private loops. There are three "interface" times defined: A more liberal AL_TIME (called PL_TIME) was agreed upon which assumes an *average* inter-node cable segment length of 500m rather than 10km. This gives a total loop length of 67km (42 miles) for a 134-node loop rather than the unrealistic worst-case of 1,340km (837 miles) assumed by FC-AL. As a result, PL_TIME is 1ms whereas AL_TIME is 15ms. LIS_HOLD_TIME was defined as the maximum amount of time a node shall hold a Loop Initialization Sequence before forwarding it to the next node. The value chosen is 1ms. LM_TOV is the minimum amount of time the Loop Master waits for a Loop Initialization Sequence to be returned before assuming the loop is not functioning. The value includes at least 126 AL_TIMEs and 126 LIS_HOLD_TIMEs, and is chosen to be 300ms. There are 4 initiator times (in addition to a ULP timer): AW_TIME, SRR_TIME, E_D_TOV, and R_A_TOV. AW_TIME is the minimum period of time an NL_Port shall wait to win arbitration before it may assume a malfunction or excessive unfairness. The value is 1 second, which takes into account 126 nodes all transmitting 64k bytes per loop tenancy at 266Mb/s, and each node unfairly arbitrating once in addition to its initial arbitration. SRR_TIME is the maximum time an Initiator assumes the Target will take to respond to a transfer of Sequence Initiative before invoking error recovery (after also taking into account physical propagation delay and arbitration time). The value may be command-dependent, workload-dependent, and/or device-dependent. Initiators may choose not to define this time specifically, but group it into a ULP timer. E_D_TOV is the minimum time an Initiator shall wait between the time it transmits a frame requesting transfer of Sequence Initiative and the time it receives a frame within the same Exchange which acknowledges the transfer of Sequence Initiative before invoking error recovery. It includes at least one AW_TIME, one SRR_TIME, and two PL_TIMEs. The value chosen is 2 seconds. Initiators may elect not to define this specifically, but group it into a ULP timer. R_A_TOV is equal to zero since private loops cannot misorder frames. Following receipt of the ACC to ABTS, Initiators may immediately transmit RRQ. A ULP timeout value is the time between the ULP dispatches a SCSI command to the interface and the time the ULP receives SCSI status. It shall be greater than or equal to E_D_TOV. There is one Target timer: R_R_TOV is a resource recovery timer used by multi-initiator targets to reclaim resources which the target has dedicated to initiators which have since "failed." It is the minimum time a target shall wait for: a) ADISC/PDISC from an initiator which has an open task, following receipt of LIP, or b) an initiator response to a transfer of Sequence Initiative before implicitly logging out that initiator, unless an ACA condition is in effect for that initiator (in which case R_R_TOV is infinite). The value chosen is 2 seconds. 4. EXCHANGE AUTHENTICATION Rather than require Targets to originate ADISC or PDISC upon expiration of RR_TOV, the Targets will instead be required to: a) suspend all open tasks until the initiators with open tasks complete the ADISC/PDISC authentication protocol, and b) implicitly log out any initiators which do not send an ADISC or PDISC no earlier than RR_TOV after the target receives a LIP. 5. LOGIN VALIDATION AND IMPLICIT LOGOUT The examples for login validation were clarified to require that when an ADISC or PDISC is sent to a target, all three identifiers (Port name, Node name, N_Port ID) must match a logged in initiator in the target or else LOGO will be returned to the initiator in response to the ADISC or PDISC. If a target supports 'N' logins and receives an N+1'th PLOGI request, a) if there were no open tasks with the least recently used initiator, that initiator may be implicitly logged out. b) if there are open tasks with all 'N' initiators, the login request shall be returned with LS_RJT and reason code "unable to perform command request." 6. FCP_RSP PAYLOAD Single-lun targets are restricted to 128-byte FCP_RSP payloads. Hosts which ONLY support single-lun direct access targets may rely on no FCP_RSP payload exceeding this value. However, hosts which support other devices or device types (e.g., controller devices) must assume those devices can return the full 255 bytes permitted by SCSI-3. 7. ACA To remain consistent with the FCSI profiles, initiators are prohibited from requiring targets to implement ACA. Prior to this, targets which did not implement ACA and Initiators which required it could not interoperate. Other profile may have additional requirements regarding host notification of configuration or logical block size changes in order to preserve data integrity without the use of ACA (see FCSI SCSI profile). 8. MULTI-LUN DISK Some high-capacity (8+Gbyte) drives must use multiple LUNs in order to make full use of their capacity on some operating systems. Charles Binford asked the question of where the LUN should be specified in the FCP_LUN field of the FCP_CMND payload. The consensus was to use the "first level addressing" field in the SCC command set, and to report "peripheral device addressing method" (00b) per Table 5 in SCC.