SUMMARY: SCSI Bus Errors

From: Steve Gauthier (sgauthie@domainpharma.com)
Date: Mon May 24 1999 - 14:54:19 CDT


Sorry for the delay - a few people asked me for the solution because they
two were having the problems and could use the insight I might gain. The
delay was due to the fact that testing all the options took much time.
Mix that in with my regular duties and this is what you get. Not my
intension to leave people hanging but I had to be realistic. Plus I made
sure I was thorough in my testing.

My original question:
> Can anyone tell me what these errors mean? I just replaced the drive
and
> these same errors appear! So I assume it's not a problem with the drive
> but the SCSI controller?
>
> Thanks,
> -Steve
>
> May 13 17:07:14 mus021p unix: WARNING:
> /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000 (esp0):
> May 13 17:07:14 mus021p unix: Connected command timeout for Target 2.0
> May 13 17:07:18 mus021p unix: WARNING:
> /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000 (esp0):
> May 13 17:07:18 mus021p unix: Target 2.0 reducing sync. transfer rate
> May 13 17:07:18 mus021p unix: WARNING:
> /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000/sd@2,0
(sd2):
> May 13 17:07:18 mus021p unix: SCSI transport failed: reason 'timeout'
> May 13 17:07:18 mus021p unix: : retrying command
Thanks to all that replied! Here's the list:
Jim Musso
Erwin Fritz
Kevin Sheehan
Blayne Puklich
Richard Smith
Steve Boronski
Birger Wathne
Chad Price
Alex Vinson
Sean ???
Damon LaCaille
Brion Leary
Bill Fenwick
Doublas L. Purdy
Scott Kulp

The responses/solutions can be placed into 3 categories:

1. Not using all FAST SCSI drives
2. Bad cable, bad cable length or inappropriate cable for a FAST SCSI bus
3. Bad termination or improper termination

Solution #1 wasn't the case since all my drives are FAST SCSI - unless
Seagate was lying in their specifications!

Solution #2 seemed to be the case because when I shorted the chain length,
I no longer got the errors. (FYI, I could reproduce the error 10 out of
10 times)

Solution #3 all terminators were replaced and all drives and external cases
were checked for termination misconfigurations.

I especially want to thank Jim Musso for providing a Sun Document that
shedded much light on the subject. I've appended the document to the end.

What I noticed (with help from that document) was that the system, after
the timeout errors, would drop the speed of the bus. This could be
observed through the use of the 'prtconf -v' command looking for the
section near the top on the ESP device. I could have made the drives
work okay by setting, in the kernel (/etc/system), a directive to set the
SCSI bus to 5MB/sec (as apposed to 10MB/sec FAST SCSI). But my user
needed full speed so I resolved the issue by replacing an external case
with one that allowed me to use a shorter cable between external cases and
removing one disk that wasn't really being used.

-Steve

SunSolve Document infodoc/2104
---------------------------------------------------------------------------
-
SYNOPSIS:
 guidelines for support of fast (10MB/sec) SCSI systems
DETAIL DESCRIPTION:
SCSI Configurations using Single-Ended Devices
SCOPE:
        The high performance SCSI devices now available provide
        the capability of significantly improving system performance
        for some applications. One of the special capabilitiesof
        these devices is the ability to transfer data at a 10-megabyte-
        per-second data rate using the "fast SCSI" synchronous transfer
        timings defined by the SCSI-2 standard. These high performance
        SCSI devices are fully compatible with standard SCSI devices
        and will operate in almost all normal SCSI configurations.
        Some SCSI enclosures, cables, and terminators do not take into
        account the special loading and impedance matching requirements
        for fast SCSI. The attachment of such peripherals may cause
        systems using fast SCSI devices to operate incorrectly. Such
        nonconforming SCSI cables and enclosures include some of Sun's
        early designs and some third-party cables,terminators, and
        peripheral device enclosures.
        The installation manuals for all fast SCSI devices and all new
        Sun installation manuals contain the strong recommendation that
        fast SCSI devices not be placed on the same SCSI port with SCSI
        components that do not conform with the requirements for fast
        SCSI. This paper provides recommendations for the technical
        modifications that can be made in a SCSI system to allow the
        operation of fastSCSI and nonconforming enclosures, cables,
        or terminators on the same sys
SOLUTION SUMMARY:
1.0 IDENTIFICATION OF SUN SYSTEMS REQUIRING SPECIAL ATTENTION
        Differential SCSI host adapters and devices, including the
        DSBE/S card and the Differential SCSI Data Center Disk Tray,
        are all designed to meet fast SCSI requirements and will
        operate at 10 Megabytes per second. The maximum total cable
        length of a differential SCSI system is 25 meters. The
        installation guides for theSCSI devicesindicate the
        equivalent cable length of the device.
        SCSI host systems that operate at 5 megabytes per second,
        including all Sun SPARC-based systems developed prior to the
        SPARCsystem 10, will support any presently defined
        configuration of 5 megabyte SCSI devices. A fast SCSI device
        can be installed on such systems, since the host and the fast
        SCSI device automatically negotiate the proper operational
        speed. Fast SCSI devices attached to 5 megabyte hosts will
        only operate at 5 megabytes, but the capacity and access
        latency improvements provided by many such devices can still
        improve the flexibility and performance of such systems.
        Single-ended SCSI systems operating at 5 megabytes have a
        maximum total cable length of 6 meters.
1.1 SCSI systems and host adapters that operate at 10 megabytes per
        second, including the SPARCsystem 600MP series, the SPARCsystem
        10, and the FSBE/S host adapter, will support any presently
        defined configuration of 5 megabyte devices. Again, the host
        will determine automatically that the devices are 5 megabyte
        per second devices and negotiate the proper operational speed
        with each device.
        SCSI host systems that operate at 10 megabytes per second and
        haveat least one fast SCSI device attached require that the
        entire SCSI port configuration be composed of components that
        will support fast SCSI. The components include cables, device
        enclosures, and terminators. The recent Sun SCSI products,
        including the Desktop Storage Pack, the Desktop Storage Module,
        and SCSI Expansion Pedestal are devices and enclosures that
        meet the fast SCSI requirements. The regulated terminator (Sun
        part number 150-1785-02) meets the fast SCSI requirements.The
        host will negotiate with the 10 megabyte devices to perform 10
        megabyte transfers and with each of the other devices to
        perform transfers at their preferred rates. Single-ended SCSI
        systems operating at 10 megabytes using the proper components
        have a maximum total cable length of 6 meters, in accordance
        with the proposed SCSI-3 standard.
1.2 Those Sun enclosures with the three-row 50-pin D connector,
        including the External Storage Module, do not meet the fast
        SCSI requirements. Those Sun enclosures with the
        Centronics-style 50-pin flat ribbon contact connector,
        including the Front Load 1/2-inch Tape Drive, do not meet the
        fast SCSI requirements. The Sun SCSI terminators other than
        150-1785-02 do not meet the fast SCSI requirements. Section 4
        of this paper defines the steps that must be taken to assure
        reliable operation of fast SCSI systems containing combinations
        of fast SCSI devices and components that do not meet the fast
        SCSI requirements. The maximumtotal cable length for such
        systems should not exceed 6 meters.
                         SUMMARY OF SYSTEM REQUIREMENTS
                                   TABLE 1
           | SCSI Host | fast SCSI | 5 Mbyte SCSI | Special
|
           | Type | device | device | Modifications
|
           | | installed? | installed? | Required?
|
|_____________|_____________|________________|_______________|
           | | | |
|
           | 5megabyte | don't care | don't care | no
|
|_____________|_____________|________________|_______________|
           | | | |
|
           | 10 megabyte | no | don'tcare | no
|
|_____________|_____________|________________|_______________|
           | | | |
|
           | 10 megabyte | yes | all conform | no
|
           | | | to fast SCSI |
|
           | | | requirements |
|
|_____________|_____________|________________|_______________|
           | | | |
|
           | 10 megabyte | yes | one or more | yes
|
           | | | don't conform | see section 4
|
           | | | to fast SCSI |
|
           | | | requirements |
|
|_____________|_____________|________________|_______________|
2.0 IDENTIFICATION OF MIXED VENDOR SYSTEMS REQUIRING SPECIAL
ATTENTION
  SCSI peripheral devices, connectors,and cables provided by
        companies other than Sun are not tested by Sun in the fast SCSI
        environment. If any of the following symptoms occur when using
        such devices in Sun fast SCSI systems, it may be becausethe
        peripheral device, related components, or the configuration
        does not conform to the fast SCSI requirements. The steps
        described in section 4 can usually be used to correct these
        symptoms if the components meet the standard SCSI
        requirements. The system will usually continue operating
        normally, even if these errors do occur, because as part of the
        software error recovery, the SCSI data rate is slowed to allow
        reliable operation.
        The maximum total cable length for such devices should be 6
        meters if they properly follow the recommendations of the SCSI
        standards committee.
                                CHART OF SYMPTOMS
           RELATED TO SCSI DEVICES NOT MEETING FAST SCSI REQUIREMENTS
        Sun OS 4.1.3
                 Examples of the warning system messages that occur
during
                 boot are contained in the appendix to this paper. The
                 key words of one symptom are:
                 Target 1.0 reducing sync.transfer rate
 SCSI transportfailed: reason 'reset': retrying command
                 Target 1.0 reverting to async. mode
                 SCSI transport failed: reason 'reset': retrying command
                 A second symptom may be:
               Current command timeout for Target 3 Lun 0
 Cmd dump for Target 3 Lun 0:
                 Target 3.0 reducing sync. transfer rate
                 SCSI transport failed: reason 'reset': retrying command
     A third symptom may be:
    Error for command 'read'
                 Error Level: Retryable
                 Sense Key: Aborted Command
                 Vendor 'XXYYZZ' error code: 0x47
         Sun Solaris 2.x
            Examples of the warning system messages that occur during
                 boot are contained in the appendix to this paper. The
                 key words of one symptom are:
                 WARNING: ....
                      SCSI bus DATA IN phase parity error
 WARNING: ....
                      Error for command 'read' Error Level:
Retryable
                      Sense Key: Aborted Command
                         ......
                 A second symptom may be:
        WARNING: ....
             SCSI transport failed: reason 'timeout':retrying command
       The present negotiated data rate in kilobytes per second
                 can be determined for a disk by requesting the
necessary
           data with the prtconf command as shown below. If the
                negotiated rate is lower than expected, errorrecovery
                procedures may have been executed because of
nonconforming
                devices in the configuration.
                 #prtconf -v
                         esp, unit #0
                            Driver software properties:
              name <target1-sync-speed> length <4>
                                    value <0x00002710>.
 The value 0x00002710 is 10000 kilobytes per second in decimal.
              If the boot process was not observed, the boot messages
          are stored in the file /var/adm/messages for reference.
                 The messages can be displayed by performing the
command:
                 # dmesg | more
 3.0 METHODS FOR MANAGING FAST SCSI SYSTEMS WITH NONCONFORMING
COMPONENTS
        3.1 Follow installation recommendations
        The use of fast SCSI hosts and fast SCSI peripherals provides
        significant performance improvements for some types of
        applications. To take full advantage of those performance
        improvements, the installation guides for SCSI devices
        recommend that only those components and peripheral devices
        supporting fast SCSI requirements be installed on a fast SCSI
        port. If nonconforming devices must also be installed on a
        host, a separate SCSI host adapter should be installed and all
        the nonconforming devices should be installed on that SCSI
        port, isolated from all the fast SCSI devices that are running
        on fast SCSI host adapters.
        3.2 Actively terminate SCSI configurations containing the
ESM
        The External Storage Module (ESM) is a special case, since it
        conforms to the fast SCSI requirements except for its adapter
        cable and terminator. The following procedure allows the
        correct termination of the External Storage Module and allows
        correct fast SCSI operation for all fast SCSI devices installed
        on the SCSI port as well as normal synchronous operation for
        thedevices installed in the ESM.
        One or two ESMs may be installed in the middleof a string of
        SCSI devices. Use a Desktop Storage Pack or Desktop Storage
        Module with a regulated terminator (Sun part number
        150-1785-02) as the device farthest away from the host on the
        SCSI port. Connect the ESM's into the string of SCSIdevices
        using 0.8 m Sun cables. (Sun part number 530-1829-01,
        Rev.51). Do not exceed the maximum totalcable length of 6
        meters.
        3.3 Slow all SCSI ports to asynchronous operation.
        For all other fast SCSI hosts attaching devices that do not
        conform with the fast SCSI requirements, the operating system
        should be modified to run all SCSI ports in asynchronous mode.
        This slower mode fully interlocks all the SCSI data transfer
        signals and provides for reliable operation of the Extended
        Storage Module at the end of a SCSI bus. It allows Sun
        configurations containing both fast SCSI drives and
        nonconforming devices to operate reliably on fast SCSI ports.
        If the system configuration meets the standard SCSI
        requirements, reliable operation can usually be provided
        with third-party components and peripherals as well. The
        slower data rate applies to all SCSI ports on the system. Some
        applications may show a decrease in performance because of the
        slower data rate.
     For 4.1.x. OS:
                 To change to the slower asynchronous data rate, type:
                         adb -w /vmunix
           scsi_options?W 58
                         $q
         then reboot the system.
                To turn synchronous transfer back on at the
                highest possible speed, use the same procedure,
                replacing the middle line with:
                        scsi_options?W 178
      For Solaris 2.x:
                To change to the slower asynchronous data rate,
                add the following line to /etc/system file:
            set scsi_options = 0x58
              then reboot the system.
                To turn synchronous transfer back on at the
                highest possible speed without using tagged
                queueing, change the scsi_options line to:
                        set scsi_options = 0X178
                To turn synchronous transfer back onat the
                highest possible speed allowing tagged queueing
                (if available in the operating system),
                change the scsi_options line to:
                        set scsi_options = 0X1f8
                                 APPENDIX A
                      SAMPLES OF 4.1.3 ERROR MESSAGES
 In this example, target 1 (sd1 on esp0) is a fast scsi disk
 Sep 16 15:53:23 b34a vmunix: esp0: Target 1.0 reducing sync. transfer
rate
 Sep 16 15:53:23 b34a vmunix: sd1: SCSI transport failed: reason
'reset':
                     retrying command
 Sep 16 15:53:23 b34a vmunix: esp0: Current command timeout for Target 1
Lun
 0
 Sep 16 15:53:23 b34a vmunix: esp0: State=DATA_DONE (0xa), Last
State=DATA
 (0x9)
 Sep 16 15:53:23 b34a vmunix: esp0: Cmd dump for Target 1 Lun 0:
 Sep 16 15:53:23 b34a vmunix: esp0: cdb=[0x8 0x0 0x7e 0x0 0x10 0x0 0x0
0x0
                                          0x0 0x0]
 Sep 1615:53:23 b34a vmunix: esp0: Target 1.0 reverting to async. mode
 Sep 16 15:53:23 b34a vmunix: sd1: SCSI transport failed: reason
'reset':
                   retrying command
 or
 Sep 16 15:57:41 b34a vmunix: sd3 at esp0 target 0 lun 0
 Sep 16 15:57:41 b34a vmunix: sd3: <SUN0669 cyl 1614 alt 2 hd 15 sec 54>
 Sep 16 16:01:12 b34a vmunix: esp0: Current command timeout for Target 3
Lun
 0
Sep 16 16:01:12 b34a vmunix: esp0: State=DATA_DONE (0xa), Last
State=DATA
(0x9)
 Sep 16 16:01:12 b34a vmunix: esp0: Cmd dump for Target 3 Lun 0:
 Sep 16 16:01:12 b34a vmunix:esp0: cdb=[0x8 0x0 0x0 0x0 0x7e 0x0 0x0 0x0
       0x0 0x0]
 Sep 16 16:01:12 b34a vmunix: esp0: Target 3.0 reducing sync. transfer
rate
 Sep 16 16:01:12 b34a vmunix: sd0: SCSI transport failed: reason
'reset':
                               retrying command
 Sep 16 16:01:12 b34a vmunix: sd1:SCSI transport failed: reason 'reset':
                                    retrying command
or
 Sep 16 16:36:51 b34a vmunix: sd3c: Error for command 'read'
 Sep 16 16:36:51 b34a vmunix: sd3c: Error Level: Retryable
 Sep 16 16:36:51 b34a vmunix: sd3c: Block 1386, Absolute Block: 1386
 Sep 16 16:36:51 b34a vmunix: sd3c: Sense Key: Aborted Command
 Sep 16 16:36:51 b34a vmunix: sd3c: Vendor 'MICROP' error code: 0x47
                 SAMPLES OF SOLARIS 2.x ERROR MESSAGES
 In this example internal disk 1 (target 1) is a 10 MB/sec disk:
 WARNING: /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000
 (esp0):
           SCSI bus DATA IN phase parity error
 WARNING:
 /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000/sd@1,
           0 (sd1):
         Error for command 'read' Error Level: Retryable
         Block 59640, Absolute Block: 59640
         Sense Key: Aborted Command
    Vendor 'SEAGATE' error code: 0x48 (<unknown extended sense code
                   0x48>), 0x0
 or:
 WARNING:
 /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000/sd@1,
           0 (sd1):
           SCSI transport failed: reason 'timeout': retrying command
                            APPENDIX B
 TABLE OF DEVICES, SYSTEMS, AND THEIR FAST-SCSI CHARACTERISTICS
 SYSTEMS AND HOST ADAPTERS
 Official Name SCSIData Rate
   SPARCsystem 10 fast SCSI
         424Megabyte internal Disk 5 MByte SCSI
         1.05 Gigabyte internal Disk fast SCSI
   SPARCstation 1 5 MByte SCSI
   SPARCstation 1+ 5 MByte SCSI
   SPARCstation IPC 5 MByte SCSI
   SPARCstation SLC 5 MByte SCSI
   SPARCstation IPX 5 MByte SCSI
   SPARCstation ELC 5 MByte SCSI
   SPARCstation2 5 MByte SCSI
   SPARCserver 4/330 5 MByte SCSI
   SPARCserver 4/370 5 MByte SCSI
   SPARCserver 4/390 5 MByte SCSI
   SPARCserver 630MP presently fast
SCSI
   SPARCserver 670MP presently fast
SCSI
   SPARCserver 690MP presently fast
SCSI
   SBus SCSI HostAdapter 5 MByte SCSI
   SBE/S Host Adapter 5 MByte SCSI
   FSBE/S Host Adapter fast SCSI
   DSBE/S Host Adapter differential
fast
   SCSI
 PERIPHERALS
 Official Name Common Name SCSI Data Rate
   Desktop Storage Pack Lunchbox
         207 Megabyte Disk 5 MByte SCSI
         424 Megabyte Disk 5 MByte SCSI
         Sun CD ROM 5 MByte SCSI
         150 Megabyte1/4" Tape 5 MByte SCSI
   Desktop Storage Module Dinnerbox
         1.3 Gigabyte Disk 5 MByte SCSI
         2.3 Gigabyte 8 mm Tape Drive 5 MByte SCSI
         5.0 Gigabyte 8 mm Tape Drive 5 MByte SCSI
   SCSI Expansion Pedestal Bullwinkle
         1.3 Gigabyte Disk 5 MByte SCSI
         2.3 Gigabyte 8 mm Tape Drive 5 MByte SCSI
  5.0 Gigabyte 8 mm Tape Drive 5 MByte SCSI
         Sun CD ROM 5 MByte SCSI
         2.1 Gigabyte Disk differential
fast
         SCSI
   Differential SCSI Data Center Disk Tray Tarzan
         2.1 Gigabyte Disk differential fast SCSI
   Front Load Tape Drive 1/2" tape 5 MByte SCSI
   External Storage Module P-Box 5 MByte SCSI
PATCH ID: n/a
PRODUCT AREA: n/a
PRODUCT: Prphl
SUNOS RELEASE: any
UNBUNDLED RELEASE: n/a
HARDWARE: n/a



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