Query: scsimgr_esdisk
OS: hpux
Section: 7
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
scsimgr_esdisk(7) Miscellaneous Information Manual scsimgr_esdisk(7)NAMEscsimgr_esdisk - SCSI class driver esdisk plug-in for scsimgrDESCRIPTIONThe SCSI class driver plug-in for implements management and diagnostic operations specific to classes of devices bound to the driver. is the native HP-UX SCSI class driver that handles, by default, all block devices including the following types: direct access, CD/DVD, write- once read-multiple (WORM), and optical memory (OM). The plug-in handles the following operations for driver o Displays and clears driver global statistics and the statistics it maintains on instances of LUNs bound to it, and on related LUN paths. o Displays status and other information maintained by driver on LUNs bound to it. o Gets, sets, and saves driver global, per-lun instance attributes or attributes for a set of devices bound to the driver. Commands The user can explicitly send the following commands to driver plug-in by specifying the option: Clears statistics. Displays information on attributes. Displays status and other information. Displays statistics. Saves value of attributes in a persistent store. Set current values of attributes. Refer to scsimgr(1M) for the syntax of the above commands. However, the only instance when it is necessary to explicitly send a command to the plug-in is when performing operations on objects global to driver global statistics, attributes or status information. In all the other cases, automatically invokes the plug-in to perform the driver specific part of the operation, when the operation applies to LUNs bound to driver or to their LUN paths. Attributes The following table lists driver specific attributes. Under the category "Device Set", the table lists which attributes the driver allows at a settable attribute scope (also known as Device Data Repository, DDR). Attribute scopes supported by are peripheral device type (pdt), vendor identifier (vid), product identifier (pid), and product revision (rev). See attr_scope in scsimgr(1M) for more information. The following conventions are used : o RO is Read Only. o RW is Read Write. o uint32 is unsigned 32 bit integer. o Range of values for applicable attributes is listed. ------------------------------------------------------------------------------ Object Attribute Name RO/RW Type Description ------------------------------------------------------------------------------ Global version RO string Version of driver esdisk. ------------------------------------------------------------------------------ LUN capacity RO uint32 Device capacity in number of blocks. ------------------------------------------------------------------------------ congest_max_retries RW uint32 Number of retries for device discovery I/Os during Busy or Queue Full condition. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ block_size RO uint32 Block size in bytes. ------------------------------------------------------------------------------ format_secs RW uint32 Timeout in seconds of SCSI command FORMAT. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ start_unit_secs RW uint32 Timeout in seconds of SCSI command START UNIT. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ max_retries RW uint32 Maximum number of I/O retries. Range: 1 - 0xFFFFFFFF ------------------------------------------------------------------------------ path_fail_secs RW uint32 Timeout in seconds before declaring a LUN path off- line. Range: 0 - 0xFFFFFFFE ------------------------------------------------------------------------------ esd_secs RW uint32 Maximum time in seconds for the transmission of an I/O. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ load_bal_policy RW string I/O load balancing policy. May be: round_robin least_cmd_load cl_round_robin closest_path preferred_path pref_tport weighted_rr ------------------------------------------------------------------------------ infinite_retries RW boolean Enable or disable infinite _enable retry of I/Os. May be: true(1): enable false(0): disable ------------------------------------------------------------------------------ disable_flags RW string A set of flags representing SCSI task management and other functions. If a flag is set, the corresponding function is disabled for the LUN. The following flags are currently defined: WCE: Write Cache Enable RW16: 16 bytes READ/WRITE CDB ABT: SCSI task management function Abort Task Set CTS: SCSI task management function Clear Task Set LR: SCSI task management function LUN Reset WTR: SCSI task management function Warm Target Reset CTR: SCSI task management function Cold Target Reset BR: Bus Reset PR: Persistent Reservation WERO: Write Exclusive Regis- trants Only Persistent Reservation EARO: Exclusive Access Reg- istrants Only Persistent Reservation ALL: Disable all functions NONE: Enable all functions ------------------------------------------------------------------------------ preferred_path RW string Hardware path, or class and instance number of the LUN path to use preferably for I/O transfer, when I/O load balancing policy is set to preferred_path. ------------------------------------------------------------------------------ pref_tport RW string Worldwide name (WWN) in hexadecimal of the target port to use preferably for I/O transfer, when I/O load balancing policy is set to pref_tport. ------------------------------------------------------------------------------ alua_enabled RW boolean Indicates whether Asymmetric Logical Unit Access (ALUA) functionality is enabled for the LUN instance. The value of true(1) indicates that ALUA functionality is han- dled if LUN supports it. The value of false(0) indi- cates that ALUA functional- ity is ignored even if LUN supports it. May be: true(1): enable ALUA false(0): disable ALUA ------------------------------------------------------------------------------ retry_delay RW boolean Enables or disables support _enabled of retry delay timer codes returned by devices comply- ing with SAM-4 (SCSI Archi- tecture Model 4), in case of congestion. If set to false(0), retry delay timer codes are ignored. If set to true(1), retry delay timer codes are taken into considera- tion, when handling conges- tion. May be: true(1): enable retry delay timer codes. false(0): disable disable retry timer codes. ------------------------------------------------------------------------------ ping_type RW string Failed LUN path connectivity test. Determines whether the system should automati- cally test the connectivity of a failed LUN path and if so which kind of test must be performed. May be set to: No connectivity test should be performed. Basic connectivity test including the Standard Inquiry command, should be performed. Extended connectivity test including Standard Inquiry and Test Unit Ready (TUR) commands should be per- formed. ------------------------------------------------------------------------------ ping_recovery RW string Failed LUN path recovery policy. Determines when a failed LUN path should be considered back online when automatic connectivity test is enabled. May be set to: Upon a successful connectiv- ity test. After a number of consecu- tive successful connectivity tests specified by the attribute Upon sustained successful connectivity tests within the time period specified in the attribute ------------------------------------------------------------------------------ ping_time _thresh- RW uint32 Minimum time in seconds, of old sustained successful connec- tivity tests before a failed LUN path is considered back online. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ ping_count _thresh- RW uint32 Minimum number of consecu- old tive successful connectivity tests before a failed LUN path is considered back online. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ Device Set transient_secs RW uint32 Seconds to wait after a LUN transitioned out of ONLINE state before failing I/Os. Range: 0 - 0xFFFFFFFE ------------------------------------------------------------------------------ congest_max_retries RW uint32 Number of retries for device discovery I/Os during Busy or Queue Full condition. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ format_secs RW uint32 Timeout in seconds of SCSI command FORMAT. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ start_unit_secs RW uint32 Timeout in seconds of SCSI command START UNIT. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ max_retries RW uint32 Maximum number of I/O retries. Range: 1 - 0xFFFFFFFF ------------------------------------------------------------------------------ path_fail_secs RW uint32 Timeout in seconds before declaring a LUN path off- line. Range: 0 - 0xFFFFFFFE ------------------------------------------------------------------------------ esd_secs RW uint32 Maximum time in seconds for the transmission of an I/O. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ max_q_depth RW uint32 Maximum queue depth. Range: 1 - 0xFFFFFFFE ------------------------------------------------------------------------------ load_bal_policy RW string I/O load balancing policy. May be set to: round_robin least_cmd_load cl_round_robin closest_path weighted_rr ------------------------------------------------------------------------------ alua_enabled RW boolean Indicates whether Asymmetric Logical Unit Access (ALUA) functionality is enabled by default. A value of true(1) indicates that by default ALUA functionality will be handled for the devices supporting it. A value of false(0) indicates that by default ALUA func- tionality will be ignored for the devices supporting it. May be: true(1): enable ALUA false(0): disable ALUA ------------------------------------------------------------------------------ disable_flags RW string A set of flags representing SCSI task management and other functions. If a flag is set, the corresponding function is disabled for the set of devices. The following flags are cur- rently defined: WCE: Write Cache Enable RW16: 16 bytes READ/WRITE CDB ABT: SCSI task management function Abort Task Set CTS: SCSI task management function Clear Task Set LR: SCSI task management function LUN Reset WTR: SCSI task management function Warm Target Reset CTR: SCSI task management function Cold Target Reset BR: Bus Reset PR: Persistent Reservation WERO: Write Exclusive Regis- trants Only Persistent Reservation EARO: Exclusive Access Reg- istrants Only Persistent Reservation ALL: Disable all functions NONE: Enable all functions ------------------------------------------------------------------------------ infinite_retries RW Boolean Enable or disable infinite _enable retries of I/Os May be: true(1): enable false(0): disable ------------------------------------------------------------------------------ retry_delay RW boolean Enables or disables support _enabled of retry delay timer codes returned by devices comply- ing with SAM-4 (SCSI Archi- tecture Model 4), in case of congestion. If set to false(0), retry delay timer codes are ignored. If set to true(1), retry delay timer codes are taken into considera- tion, when handling conges- tion. May be: true(1): enable retry delay timer codes. false(0): disable disable retry delay timer codes. ------------------------------------------------------------------------------ ping_type RW string Failed LUN path connectivity test. Determines whether the system should automati- cally test the connectivity of a failed LUN path and if so which kind of test must be performed. May be set to: No connectivity test should be performed. Basic connectivity test including Standard Inquiry command, should be per- formed. Extended connectivity test including Standard Inquiry and Test Unit Ready (TUR) commands should be per- formed. ------------------------------------------------------------------------------ ping_recovery RW string Failed LUN path recovery policy. Determines when a failed LUN path should be considered back online when automatic connectivity test is enabled. May be set to: Upon a successful connectiv- ity test. after a number of consecu- tive successful onnectivity tests specified by the attribute Upon sustained successful connectivity tests within the time period specified in the attribute ------------------------------------------------------------------------------ ping_time _thresh- RW uint32 Minimum time in seconds, of old sustained successful connec- tivity tests before a failed LUN path is considered back online. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ ping_count _thresh- RW uint32 Minimum number of consecu- old tive successful connectivity tests before a failed LUN path is considered back online. Range: 0 - 0xFFFFFFFF ------------------------------------------------------------------------------ I/O Load Balancing Policy The I/O load balancing policy attribute, is a tunable that controls how I/Os are distributed across the paths to a LUN: o LUN paths are selected in a round robin manner. This is more appropriate when all the paths to the device have similar I/O turn- around characteristics. o The LUN path with the least number of active I/O requests is selected to execute the next I/O. This policy is appropriate when the paths to the LUN exhibit asymmetric latency characteristics. The load is distributed to optimize the bandwidth on each LUN path. o This load balancing policy is applicable to HP cell-based platforms. The LUN paths are selected in a round robin manner within the locality of CPU on which the I/O was initiated, to ensure that memory access latencies are optimized. o The LUN path set in the attribute is preferably used for I/O transfer. If this LUN path is not available or if the attribute was not set, any other path is selected for I/O transfer. This policy is useful for certain disk arrays, where some paths may be optimized for I/O transfer to certain LUNs. The attribute can be set with the hardware path, or the combination of the class and instance number of the preferred LUN path. For example for a LUN path with instance number 100, the combination of class and instance number is: In a normal output display for this attribute, both the hardware path and the combination of class and instance number of the preferred LUN path are displayed (Example: In scriptable output for this attribute, only the hardware path of the preferred LUN path is displayed (Example: o The LUN path is selected based on its affinity with the CPU issuing the I/O so as to minimize latency. This policy is more appropri- ate on cell based platforms. o LUN paths to the target port set in the attribute are preferably used for I/O transfer in a round robin manner, when the I/O load bal- ancing policy is set to If no LUN path to the preferred target port is available, or if the attribute is not set, any other path is selected for I/O transfer. This policy is appropriate for certain disk arrays, where some target ports are optimized for I/O transfer to certain LUNs. o Weighted Round Robin. I/Os are distributed between the LUN paths in a round robin manner and according to the weight assigned to each path (via the LUN path attribute A number of I/Os corresponding to the weight of the path is transferred on the path before another path is selected.EXAMPLESTo display plug-in general help and supported commands: To get esdisk driver global statistics: To clear esdisk driver global statistics: To get esdisk driver global status information: To display information about esdisk driver global attributes: To set the I/O load balancing policy for disk0 to and set the I/O path to be used preferably: To set the I/O load balancing policy for disk1 to and set the preferred target port to 0x50001fe150006e6d: To add a settable attribute scope corresponding to all disk devices from HP with product identifier "MSA VOLUME", for allowing modification of some settable attribute at this scope: To persistently change the default I/O load balancing policy, I/O timeout, and maximum concurrent I/O for all disk devices from HP with product identifier "MSA VOLUME:" To disable write cache, Persistent Reservation and 16 bytes read/write CDB for all disk devices bound to the driver:AUTHORSCSI class driver plug-in for was developed by Hewlett-Packard Company.SEE ALSOdiskinfo(1M), scsictl(1M), scsimgr(1M), intro(7), scsi(7), scsi_disk(7). scsimgr_esdisk(7)