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man pages section 4: Device and Network Interfaces

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Updated: Thursday, June 13, 2019
 
 

sd (4D)

Name

sd - SCSI disk and ATAPI/SCSI CD-ROM device driver

Synopsis

sd@target,lun:partition

Description

To open a device without checking if the vtoc is valid, use the O_NDELAY flag. When the device is opened using O_NDELAY, the first read or write to the device that happens after the open results in the label being read if the label is not currently valid. Once read, the label remains valid until the last close of the device. Except for reading the label, O_NDELAY has no impact on the driver.

SPARC

The sd SCSI and SCSI/ATAPI driver supports embedded SCSI-2 and CCS-compatible SCSI disk and CD-ROM drives, ATAPI 2.6 (SFF-8020i)-compliant CD-ROM drives, SFF-8090–compliant SCSI/ATAPI DVD-ROM drives, IOMEGA SCSI/ATAPI ZIP drives, SCSI JAZ drives, and USB mass storage devices (refer to scsa2usb(4D)).

To determine the disk drive type, use the SCSI/ATAPI inquiry command and read the volume label stored on block 0 of the drive. (The volume label describes the disk geometry and partitioning and must be present for the disk to be mounted by the system.) A volume label is not required for removable, re-writable or read-only media.

x86 Only

The sd driver supports embedded SCSI-2 and CCS-compatible SCSI disk and CD-ROM drives, ATAPI 2.6 (SFF-8020i)-compliant CD-ROM drives, SFF-8090-compliant SCSI/ATAPI DVD-ROM drives, IOMEGA SCSI/ATAPI ZIP drives, and SCSI JAZ drives.

The x86 BIOS legacy requires a master boot record (MBR) and fdisk table in the first physical sector of the bootable media. If the x86 hard disk contains a Solaris disk label, it is located in the second 512-byte sector of the FDISK partition.

DEVICE SPECIAL FILES

Block-files access the disk using normal buffering mechanism and are read-from and written-to without regard to physical disk records. A raw interface enables direct transmission between the disk and the user's read or write buffer. A single read or write call usually results in a single I/O operation, therefore raw I/O is more efficient when many bytes are transmitted. Block files names are found in /dev/dsk; raw file names are found in /dev/rdsk.

I/O requests to the raw device must be aligned on a 512-byte (DEV_BSIZE) boundary and all I/O request lengths must be in multiples of 512 bytes. Requests that do not meet these requirements will trigger an EINVAL error. There are no alignment or length restrictions on I/O requests to the block device.

CD-ROM DRIVE SUPPORT

A CD-ROM disk is single-sided and contains approximately 640 megabytes of data or 74 minutes of audio. When the CD-ROM is opened, the eject button is disabled to prevent manual removal of the disk until the last close() is called. No volume label is required for a CD-ROM. The disk geometry and partitioning information are constant and never change. If the CD-ROM contains data recorded in a Solaris-aware file system format, it can be mounted using the appropriate Solaris file system support.

DVD-ROM DRIVE SUPPORT

DVD-ROM media can be single or double-sided and can be recorded upon using a single or double layer structure. Double-layer media provides parallel or opposite track paths. A DVD-ROM can hold from between 4.5 Gbytes and 17 Gbytes of data, depending on the layer structure used for recording and if the DVD-ROM is single or double-sided.

When the DVD-ROM is opened, the eject button is disabled to prevent the manual removal of a disk until the last close() is called. No volume label is required for a DVD-ROM. If the DVD-ROM contains data recorded in a Solaris-aware file system format, it can be mounted using the appropriate Solaris file system support.

ZIP/JAZ DRIVE SUPPORT

ZIP/JAZ media provide varied data capacity points; a single JAZ drive can store up to 2 GBytes of data, while a ZIP-250 can store up to 250MBytes of data. ZIP/JAZ drives can be read-from or written-to using the appropriate drive.

When a ZIP/JAZ drive is opened, the eject button is disabled to prevent the manual removal of a disk until the last close() is called. No volume label is required for a ZIP/JAZ drive. If the ZIP/JAZ drive contains data recorded in a Solaris-aware file system format, it can be mounted using the appropriate Solaris file system support.

DEVICE STATISTICS SUPPORT

Each device maintains I/O statistics for the device and for partitions allocated for that device. For each device/partition, the driver accumulates reads, writes, bytes read, and bytes written. The driver also initiates hi-resolution time stamps at queue entry and exit points to enable monitoring of residence time and cumulative residence-length product for each queue.

Not all device drivers make per-partition IO statistics available for reporting. sd and ssd(4D) per-partition statistics are enabled by default but may disabled in their configuration files.

SCSI FMA phase III

Based on the implementation of SCSI FMA phase III, the sd driver is able to send out FMA telemetries (ereports) when detecting an error condition. The ereports detail what is happening at the kernel driver level.

Error Reports and Payloads

Ereports (error reports) are generated upon the detection of an abnormal condition, recorded in persistent storage (for example a file system) in binary format, and used as input to automated diagnosis engines.

An ereport is described by its event class (hierarchy path) and a payload of name-value pairs that can be used for diagnosis and logging.

Six new ereports are introduced by SCSI FMA:

  • ereport.io.scsi.cmd.disk.dev.rqs.merr -- Media error

  • ereport.io.scsi.cmd.disk.dev.rqs.derr -- Device error

  • ereport.io.scsi.cmd.disk.dev.serr -- SCSI command status error

  • ereport.io.scsi.cmd.disk.dev.uderr -- Unexpected data error

  • ereport.io.scsi.cmd.disk.recovered -- SCSI command recovered from a failure

  • ereport.io.scsi.cmd.disk.tran -- SCSI command transport error

There are many payloads along with these ereports. For analyzing problems, ENA and driver-assessment are quite useful.

ENA (error numeric association) is used in SCSI FMA as a link for a sequence of related ereports. For example, a command retried several times that finally succeeds would result in a sequence of posted ereports that are associated by the same ENA value.

The driver-assessment value is used to indicate the action the driver is going to take. Usually this value is helpful for the administrator to analyze what happened to a specific SCSI command at the kernel level. The table in the “driver-assessment values” section below lists the available values of driver-assessment .

Other useful payloads for analyzing SCSI FMA reports are listed in the following table.

Payload Name
Description
ENA
Error Numeric Association. Can be used to associate a series of related ereports.
detector
The device that detected the error condition.
cdb
Command Description Block.
driver-assessment
The action the driver is going to take.
op-code
The SCSI command that resulted in the error condition.
pkt-reason
Refer to the man page for scsi_pkt(9s), pkt-reason section.
pkt-state
Refer to the man page for scsi_pkt(9s), pkt-state section.
pkt-stats
Refer to the man page of scsi_pkt(9s), pkt-statistics section.
stat-code
SCSI STATUS Code of the SCSI command.
key
Sense key of the SCSI command.
asc
Additional Sense Code.
ascq
Additional Sense Code Qualifier.
sense-data
SCSI Sense data sent back from the device.
lba
Logical Block Address on the device.
un-decode-info
Usually indicating the payload that is storing an unexpected value or other information as a hint of undecodable value.
un-decode-value
Could be empty or be used together with un-decode-info to indicate the undecodable value.

FMA Utilities

The following utilities are useful for inspecting details of ereports:

fmdump(8)

A fault management log viewer. The FMA framework maintains two categories of logs: one for faults and another for ereports. Using fmdump you can see the detail of a specific pattern of ereports and also the fault list produced by the diagnosis engine.

fmadm(8)

A tool for fault management configuration. It provides many functions, some of them quite frequently used, including viewing the faulty system component and resolving a fault.

Both these utilities need to be run as root. The following table lists some example usage of these utilities:

Example Usage
Description
fmdump -ev
Show the ereport list with ENA.
fmdump -e -n payload=value
Show ereports that match the specified pattern.
fmdump -eV
Show ereport details, usually combined with -n option
fmdump -V -u UUID
Show fault details with given UUID
fmadm faulty -u UUID
Display status information for faulty resources with given UUID
fmadm repair UUID
Set the status of a faulty device with given UUID back to normal.

Driver-assessment Values

The following table lists the available values of driver-assessment:

Value
Description
fatal
SD driver failed the current SCSI command due to a non-recoverable device error (sense-key 0x3h or 0x4h).
fail
The scsi driver is not going to stop the service but it cannot guarantee normal service.
info
The driver has detected an error, but the services provided by the device instance are unaffected.
retry
The scsi driver is going to retry a failed command and the service is unaffected.
recovered
The SD driver has recovered a SCSI command and the service is unaffected.

See the Example section of this manual page for examples of ereports.

Ioctls

Refer to dkio(4I), and cdio(4I)

Errors

EACCES

Permission denied

EBUSY

The partition was opened exclusively by another thread

EFAULT

The argument features a bad address

EINVAL

Invalid argument

ENOTTY

The device does not support the requested ioctl function

ENXIO

During opening, the device did not exist. During close, the drive unlock failed

EROFS

The device is read-only

EAGAIN

Resource temporarily unavailable

EINTR

A signal was caught during the execution of the ioctl() function

ENOMEM

Insufficient memory

EPERM

Insufficient access permission

EIO

An I/O error occurred. Refer to notes for details on copy-protected DVD-ROM media.

CONFIGURATION

The sd driver can be configured by defining properties in the sd.conf file. The sd driver supports the following properties:

allow-error-recovery-reset

The default value is 1, which allows resetting to occur. Set this value to 0 (zero) to prevent the sd driver from calling scsi_reset(9F) with a second argument of RESET_TARGET when in error-recovery mode. This scsi_reset(9F) call may prompt the HBA driver to send a SCSI Bus Device Reset message. The scsi_reset(9F) call with a second argument of RESET_TARGET may result from an explicit request via the USCSICMD ioctl. Some high-availability multi-initiator systems may wish to prohibit the Bus Device Reset message; to do this, set the allow-error-recovery-reset property to 0.

enable-partition-kstats

The default value is 1, which causes partition IO statistics to be maintained. Set this value to zero to prevent the driver from recording partition statistics. This slightly reduces the CPU overhead for IO, minimizes the amount of sar(1) data collected and makes these statistics unavailable for reporting by iostat(8) even though the –p/–P option is specified. Regardless of this setting, disk IO statistics are always maintained.

optical-device-bind

Controls the binding of the driver to non self-identifying SCSI target optical devices. (See scsi(5)). The default value is 1, which causes sd to bind to DTYPE_OPTICAL devices (as noted in scsi(5)). Setting this value to 0 prevents automatic binding. The default behavior for the SPARC-based sd driver prior to Solaris 9 was not to bind to optical devices.

power-condition

Boolean type, when set to False, it indicates that the disk does not support power condition field in the START STOP UNIT command.

qfull-retries

The supplied value is passed as the qfull-retries capability value of the HBA driver. See scsi_ifsetcap(9F) for details.

qfull-retry-interval

The supplied value is passed as the qfull-retry interval capability value of the HBA driver. See scsi_ifsetcap(9F) for details.

In addition to the above properties, some device-specific tunables can be configured in sd.conf using the sd-config-list global property. The value of this property is a list of duplets. The formal syntax is:


sd-config-list = <duplet> [, <duplet> ]* ;

where 

<duplet>:= "<vid+pid>" , "<tunable-list>"

and 

<tunable-list>:= <tunable>[, <tunable> ]*;
<tunable> = <name> : <value>

The <vid+pid> is the string that is returned by the target device
on a SCSI inquiry command.

The <tunable-list> contains one or more tunables to apply to
all target devices with the specified <vid+pid>.

Each <tunable> is a <name> : <value> pair. Supported
tunable names are:
  
   delay-busy: when busy, nsecs of delay before retry.
   
   retries-timeout: retries to perform on an IO timeout.

   disable-caching: to disable cache, set this boolean property to true.  

rmw-type

Configure the behavior for a given device (4k native disk) dealing with misaligned IOs. It can be set to,

0 : Do  RMW  (READ MODIFY WRITE)  with
    warning message.
1 : Do RMW without warning message.
2 : Do NOT do RMW and return error.

The following warning message is displayed on the console:

Write requests are not aligned to the physical sector size (4096 bytes). Although they are handled 
through Read-Modify-Write operations, it may result in performance degradation.

    There is I/O error statistic for Non-Aligned Writes. You can use the following commands to track these occurrences:

  • iostat -E

  • kstat -c device_error -s "Non-Aligned Writes"

emulation-rmw

Turns RMW support on or off in the sd driver for 512e disks in the emulation mode. Use 0 to turn off and 1 to turn on. Default is off. Emulation mode drive is a disk that has different physical block size and logical block size. This improves the throughputs of some SSDs that have bad RMW performance in firmware.

mmc-gesn-polling

For optical drives compliant with MMC-3 and supporting the GET EVENT STATUS NOTIFICATION command, this command is used for periodic media state polling, usually initiated by the DKIOCSTATE dkio(4I) ioctl. To disable the use of this command, set this boolean property to false. In that case, either the TEST UNIT READY or zero-length WRITE(10) command is used instead.

physical-block-size

SCSI Disk drivers take this value as the physical block size of the disks that do not report valid physical block size. The value must be a power of two. If not specified, DEV_BSIZE(512 bytes) is implied.

fm-log-enabled

Controls the flag that enables logging of FMA events. The default value is 0, which causes sd to disable the ability to print any log for FMA events. Setting this value to 1 enables sd to print FMA events to /var/adm/messages and to the console.

unmap-deduplication

This tunable is intended for special LUNs which internally support deduplication, but are not able to report this feature by SCSI protocol. Setting this tunable will enable the sd driver to report block unmap support to file system. And when the filesystem asks for unmap operation, the appropriate blocks will be rewritten by zeroes. Allowed parameter is non-negative integer. The value specifies the maximum length of rewritten chunk at one time in logical blocks. Zero value (recommended) will cause auto-adjustment. When the tunable is not set, only unmap operations reported by SCSI protocol will be used.

Examples

Example 1 Example of a global sd-config-list property.

The following is an example of a global sd-config-list property:
  
   sd-config-list =
      "SUN     T4", "delay-busy:6000000000, retries-timeout:6",
      "SUN     StorEdge_3510", "retries-timeout:3";

Example 2 Example of an ereport where the driver-assessment value is fail.
Apr 04 2010 01:30:23.464768275 ereport.io.scsi.cmd.disk.dev.uderr
nvlist version: 0
        class = ereport.io.scsi.cmd.disk.dev.uderr
        ena = 0xde0cd54f84201c01
        detector = (embedded nvlist)
        nvlist version: 0
                version = 0x0
                scheme = dev
                device-path = /pci@0,0/pci8086,25f8@4/pci108e,286@0/disk@5,0
                devid = id1,sd@TSun_____STK_RAID_INT____EA4B6F24
        (end detector)

        driver-assessment = fail
        op-code = 0x1a
        cdb = 0x1a 0x0 0x8 0x0 0x18 0x0
        pkt-reason = 0x0
        pkt-state = 0x1f
        pkt-stats = 0x0
        stat-code = 0x0
        un-decode-info = sd_get_write_cache_enabled: Mode Sense caching
page code mismatch 0

        un-decode-value        __ttl = 0x1
        __tod = 0x4bb7cf8f 0x1bb3cd13
Example 3 Example of an ereport where the driver-assessment value is fatal.
Jan 20 2011 18:50:16.276742278 ereport.io.scsi.cmd.disk.dev.rqs.merr
nvlist version: 0
        class = ereport.io.scsi.cmd.disk.dev.rqs.merr
        ena = 0xf83e2f0e78101c01
        detector = (embedded nvlist)
        nvlist version: 0
                version = 0x0
                scheme = dev
                device-path = /pci at 0,0/pci8086,340e at 7/pci1000,3080 
at 0/iport at f0/disk at w500 0c50010384d1d,0
                devid = id1,sd at n5000c50010384d1f
        (end detector)

        driver-assessment = fatal
        op-code = 0x28
        cdb = 0x28 0x0 0x9 0xcb 0x6f 0x0 0x0 0x0 0x80 0x0
        pkt-reason = 0x0
        pkt-state = 0x3f
        pkt-stats = 0x0
        stat-code = 0x2
        key = 0x3
        asc = 0x11
        ascq = 0x0
        sense-data = 0xf0 0x0 0x3 0x9 0xcb 0x6f 0x77 0xa 0x0 0x0 0x0 0x0
0x11 0x0 0x81 0x80 0x0 0x9d 0 xdd 0xba
        lba = 0x9cb6f00
        __ttl = 0x1
        __tod = 0x4d3883e8 0x107ec086
Example 4 Example of an ereport where the driver-assessment value is recovered.
Okt 08 2010 10:51:12.889604904 ereport.io.scsi.cmd.disk.recovered
nvlist version: 0
       class = ereport.io.scsi.cmd.disk.recovered
       ena = 0x92500a9c0ca01801
       detector = (embedded nvlist)
       nvlist version: 0
              version = 0x0
              scheme = dev
              device-path = /pci <at> 0,0/pci8086,3410 <at> 9/pci1077,
138 <at> 0/fp <at> 0,0/disk <at> w2100001378ac026e,0
              devid = id1,sd <at> n2034001378ac026e
       (end detector)

       driver-assessment = recovered
       op-code = 0x8a
       cdb = 0x8a 0x0 0x0 0x0 0x0 0x3 0x1a 0x49 0x7e 0xa9 0x0 0x0 0x1 0x0 0x0 0x0
       pkt-reason = 0x0
       pkt-state = 0x1f
       pkt-stats = 0x0
       __ttl = 0x1
       __tod = 0x4caedb80 0x35064b28
Example 5 Example of an ereport where the driver-assessment value is retry.
Jan 09 2012 10:04:31.334477741 ereport.io.scsi.cmd.disk.dev.rqs.derr
nvlist version: 0
        class = ereport.io.scsi.cmd.disk.dev.rqs.derr
        ena = 0xc3ca9ccb73e00c01
        detector = (embedded nvlist)
        nvlist version: 0
                version = 0x0
                scheme = dev
                device-path = 
/pci at 0,0/pci8086,3410 at 9/pci15d9,400 at 0/iport at 80/disk at w5000c50033f5bfb9,0
                devid = id1,sd at n5000c50033f5bfbb
        (end detector)

        devid = id1,sd at n5000c50033f5bfbb
        driver-assessment = retry
        op-code = 0x28
        cdb = 0x28 0x0 0x11 0x5d 0x75 0xf9 0x0 0x1 0x0 0x0
        pkt-reason = 0x0
        pkt-state = 0x37
        pkt-stats = 0x0
        stat-code = 0x2
        key = 0x6
        asc = 0x29
        ascq = 0x2
        sense-data = 0x70 0x0 0x6 0x0 0x0 0x0 0x0 0xa 0x0 0x0 0x0 0x0 
0x29 0x2 0x2 0x0 0x0 0x0 0xdd 0xba
        __ttl = 0x1
        __tod = 0x4f0b2c2f 0x13efb9ad

Files

/kernel/drv/sd.conf

Driver configuration file

/dev/dsk/cntndnsn

Block files

/dev/rdsk/cntndnsn

Raw files

Where:

cn

controller n

tn

SCSI target id n (0-6)

dn

SCSI LUN n (0-7 normally; some HBAs support LUNs to 15 or 32. See the specific manual page for details).

sn

partition n (0-7)

x86 Only

/dev/rdsk/cntndnpn

raw files

Where:

pn

Where n=0 the node corresponds to the entire disk.

See Also

sar(1), close(2), ioctl(2), lseek(2), read(2), write(2), scsa2usb(4D), ssd(4D), hsfs(4FS), pcfs(4FS), udfs(4FS), cdio(4I), dkio(4I), driver.conf(5), scsi(5), filesystem(7), cfgadm_scsi(8), fdisk(8), fmadm(8), fmdump(8), format(8), iostat(8), scsi_ifsetcap(9F), scsi_reset(9F), scsi_pkt(9S)

ANSI Small Computer System Interface-2 (SCSI-2)

ATA Packet Interface for CD-ROMs, SFF-8020i

Mt.Fuji Commands for CD and DVD, SFF8090v3

Diagnostics

Error for Command:<command name>
Error Level: Fatal
Requested Block: <n>
Error  Block: <m>
Vendor:'<vendorname>'
Serial Number:'<serial number>'
Sense Key:<sense key name>
ASC: 0x<a> (<ASC name>), ASCQ: 0x<b>, FRU: 0x<c>

The command indicated by <command name> failed. The Requested Block is the block where the transfer started and the Error Block is the block that caused the error. Sense Key, ASC, and ASCQ information is returned by the target in response to a request sense command.

Caddy not inserted in drive

The drive is not ready because no caddy has been inserted.

Check Condition on REQUEST SENSE

A REQUEST SENSE command completed with a check condition. The original command will be retried a number of times.

Label says <m> blocks Drive says <n> blocks

There is a discrepancy between the label and what the drive returned on the READ CAPACITY command.

Not enough sense information

The request sense data was less than expected.

Request Sense couldn't get sense data

The REQUEST SENSE command did not transfer any data.

Reservation Conflict

The drive was reserved by another initiator.

SCSI transport failed: reason 'xxxx': {retrying|giving up}

The host adapter has failed to transport a command to the target for the reason stated. The driver will either retry the command or, ultimately, give up.

Unhandled Sense Key<n>

The REQUEST SENSE data included an invalid sense.

Unit not ready. Additional sense code 0x

<n> The drive is not ready.

Can't do switch back to mode 1

A failure to switch back to read mode 1.

Corrupt label - bad geometry

The disk label is corrupted.

Corrupt label - label checksum failed

The disk label is corrupted.

Corrupt label - wrong magic number

The disk label is corrupted.

Device busy too long

The drive returned busy during a number of retries.

Disk not responding to selection

The drive is powered down or died

Failed to handle UA

A retry on a Unit Attention condition failed.

I/O to invalid geometry

The geometry of the drive could not be established.

Incomplete read/write - retrying/giving up

There was a residue after the command completed normally.

No bp for direct access device format geometry

A bp with consistent memory could not be allocated.

No bp for disk label

A bp with consistent memory could not be allocated.

No bp for fdisk

A bp with consistent memory could not be allocated.

No bp for rigid disk geometry

A bp with consistent memory could not be allocated.

No mem for property

Free memory pool exhausted.

No memory for direct access device format geometry

Free memory pool exhausted.

No memory for disk label

Free memory pool exhausted.

No memory for rigid disk geometry

The disk label is corrupted.

No resources for dumping

A packet could not be allocated during dumping.

Offline

Drive went offline; probably powered down.

Requeue of command fails

Driver attempted to retry a command and experienced a transport error.

sdrestart transport failed()

Driver attempted to retry a command and experienced a transport error.

Transfer length not modulo

Illegal request size.

Transport of request sense fails()

Driver attempted to submit a request sense command and failed.

Transport rejected()

Host adapter driver was unable to accept a command.

Unable to read label

Failure to read disk label.

Unit does not respond to selection

Drive went offline; probably powered down.

Notes

DVD-ROM media containing DVD-Video data may follow/adhere to the requirements of content scrambling system or copy protection scheme. Reading of copy-protected sector will cause I/O error. Users are advised to use the appropriate playback software to view video contents on DVD-ROM media containing DVD-Video data.

The sd driver can handle 4096 LUNs on x86 and 32,768 LUNs on SPARC. In order to increase this limit to 32,768 LUNs on x86 and 262,144 LUNs on SPARC, add the following line to/etc/system:

set devt_version = 2

Once this has been done on a system, the devt_version (1 by default) should not be changed back to 1.