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HP XP P9500 Hitachi Dynamic Link Manager Software User Guide for VMWare (HIT52 - Page 36

When an Intermittent Error Does Not Occur

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When an Intermittent Error Does Not Occur If an error does not occur on a path a specified number of times within a specified interval, an intermittent error will not occur. In such a case, the error monitoring will finish when the specified error-monitoring interval finishes, upon which the number of errors is reset to 0. If an error occurs on the path again at a later time, error monitoring will resume when the path is recovered from the error via an automatic failback. If it takes a long time for an error to occur, an intermittent error can be more easily detected by increasing the error-monitoring interval or by decreasing the number of times that the error needs to occur. Figure 2-11 What Will Happen When an Intermittent Error Does Not Occur on a Path on page 2-18 shows what will happen when an intermittent error does not occur. For this example, the path is determined to have an intermittent error if the error occurs three or more times in 30 minutes. The events that occur are described by using the time arrows. Figure 2-11 What Will Happen When an Intermittent Error Does Not Occur on a Path As shown in Figure 2-11 What Will Happen When an Intermittent Error Does Not Occur on a Path on page 2-18, normally, the count for the number of times that an error occurs is started after the path is first recovered from an error by using the automatic failback function. However, if all the paths connected to the LU are in the Offline(E), or Offline(C) status (which is due to the disconnection of the paths or some other reason), the paths will not be recovered and put back online by using the automatic failback function. If I/O operations are continuously being issued to such an LU, the count for the number of times that the error occurs might be started even though the path will not be placed online. If the number of times that the error occurs reaches the specified value, the path is determined to have an intermittent error. In such a case, remove the cause of the error, and then manually place the path online. When the Conditions for an Intermittent Error Are Changed During Error Monitoring When the conditions for an intermittent error are changed during error monitoring, the number of errors and the amount of time that has passed 2-18 HDLM Functions Hitachi Dynamic Link Manager User Guide (for VMware(R))

Section	Page
User Guide (for VMware(R))	1
Contents	3
Preface	9
Intended audience	10
Product version	10
Release notes	10
Document revision level	10
Document organization	10
Referenced documents	11
Document conventions	11
Convention for storage capacity values	13
Getting help	13
Comments	14
Overview of HDLM	15
What is HDLM?	16
HDLM Features	17
HDLM Functions	19
Devices Managed by HDLM	20
System Configuration	20
LU Configuration	21
Program Configuration	22
HDLM driver and NMP positions	23
Distributing a Load Using Load Balancing	24
Paths to Which Load Balancing Is Applied	26
Load Balancing Algorithms	27
Performing Failovers and Failbacks Using Path Switching	29
Automatic Path Switching	29
Manual Path Switching	31
Path Status Transition	32
Monitoring Intermittent Errors	34
Checking Intermittent Errors	34
Setting Up Intermittent Error Monitoring	34
Intermittent Error Monitoring Actions	35
When a User Changes the Intermittent Error Information	37
Detecting Errors by Using Path Health Checking	39
Error Management	39
Types of Collected Logs	40
Collecting Error Information Using the Utility for Collecting HDLM Error Information (DLMgetras)	41
Collecting Audit Log Data	41
Categories and Audit Events that HDLM Can Output to the Audit Log	43
Requirements for Outputting Audit Log Data	44
Destination and Filtering of Audit Log Data	45
Audit Log Data Formats	45
Creating an HDLM Environment	49
HDLM System Requirements	50
Hosts and OSs Supported by HDLM	50
Storage Systems Supported by HDLM	50
Memory and Disk Capacity Requirements	51
Number of Paths Supported in HDLM	51
Flow for Creating an HDLM Environment	52
HDLM Installation Types	52
Notes on Creating an HDLM Environment	52
Installing HDLM	53
Performing a New Installation of HDLM	53
Performing a Re-installation of HDLM	56
Checking the Path Configuration	56
Setting Up HDLM	57
Checking the Current Settings	57
Setting Up the HDLM Functions	58
Checking the Updated Settings	60
Setting Up Integrated Traces	61
Uninstalling HDLM	63
Preparations for HDLM Uninstallation	63
Uninstalling HDLM	64
HDLM Operation	67
HDLM Operations Using Commands	68
Notes on Using Commands	68
Viewing Path Information	68
Changing the Status of Paths	69
Viewing LU Information	70
Initializing Statistical Information for Paths	71
Viewing and Setting Up the Operating Environment	71
Viewing License Information	72
Updating the License	73
Viewing HDLM Version Information	73
Troubleshooting	75
Information Collected by the DLMgetras Utility for Collecting HDLM Error Information	76
Checking Error Information in Messages	76
What To Do for a Path Error	76
Examining the Messages	78
Obtain Path Information	78
Identifying the Error Path	78
Narrowing Down the Hardware That Might Have Caused the Error	78
Identifying the Error Location and Correcting any Hardware Error	78
Placing the Path Online	78
What To Do for a Program Error	79
Examining the Messages	79
Obtaining Program Information	79
What To Do for the Program Error	80
Contacting your HDLM Vendor or Maintenance Company	80
What To Do for Other Errors	80
Command Reference	81
Overview of the HDLM Command dlnkmgr	82
clear (Returns the Path Statistics to the Initial Value)	83
Format	83
Parameters	84
help (Displays the Operation Format)	85
Format	85
Parameter	85
offline (Places Paths Offline)	87
Format	88
Parameters	88
online (Places Paths Online)	91
Format	91
Parameters	92
set (Sets Up the Operating Environment)	95
Format	95
Parameters	96
view (Displays Information)	102
Format	102
Parameters (To display program information)	104
Utility Reference	129
The DLMgetras Utility for Collecting HDLM Error Information	130
Format	130
Parameters	130
List of Collected Error Information	131
Messages	135
Before Viewing the List of Messages	136
Format and Meaning of Message IDs	136
Terms Used in Messages and Message Explanations	136
KAPL01001 to KAPL02000	137
KAPL09001 to KAPL10000	157
KAPL10001 to KAPL11000	158
KAPL13001 to KAPL14000	163
KAPL15001 to KAPL16000	164
KAPL20001 to KAPL21000	165
KAPL21001 to KAPL22000	169
Acronyms and abbreviations	171
Glossary	177

Match case Limit results 1 per page

When an Intermittent Error Does Not Occur

If an error does not occur on a path a specified number of times within a

specified interval, an intermittent error will not occur. In such a case, the

error monitoring will finish when the specified error-monitoring interval

finishes, upon which the number of errors is reset to 0. If an error occurs on

the path again at a later time, error monitoring will resume when the path is

recovered from the error via an automatic failback.

If it takes a long time for an error to occur, an intermittent error can be more

easily detected by increasing the error-monitoring interval or by decreasing

the number of times that the error needs to occur.

Figure 2-11 What Will Happen When an Intermittent Error Does Not Occur on

a Path on page

shows what will happen when an intermittent error

does not occur. For this example, the path is determined to have an

intermittent error if the error occurs three or more times in 30 minutes. The

events that occur are described by using the time arrows.

Figure 2-11 What Will Happen When an Intermittent Error Does Not Occur

on a Path

As shown in

Figure 2-11 What Will Happen When an Intermittent Error Does

Not Occur on a Path on page

, normally, the count for the number of

times that an error occurs is started after the path is first recovered from an

error by using the automatic failback function. However, if all the paths

connected to the LU are in the

Offline(E)

, or

Offline(C)

status (which is

due to the disconnection of the paths or some other reason), the paths will

not be recovered and put back online by using the automatic failback

function. If I/O operations are continuously being issued to such an LU, the

count for the number of times that the error occurs might be started even

though the path will not be placed online. If the number of times that the

error occurs reaches the specified value, the path is determined to have an

intermittent error. In such a case, remove the cause of the error, and then

manually place the path online.

When the Conditions for an Intermittent Error Are Changed During Error

Monitoring

When the conditions for an intermittent error are changed during error

monitoring, the number of errors and the amount of time that has passed

2-18

HDLM Functions

Hitachi Dynamic Link Manager User Guide (for VMware(R))