IBM AIX Continuous Availability Features - IBM Redbooks

More documents

Recommendations

Info

Live dumps are small dumps that do not require a system restart. Only components that are registered for live dumps, and are requested to be included, are dumped. Use the dumpctrl command to obtain information about which components are registered for live dumps. Live dumps can be initiated by software programs or by users with root user authority. Software programs use live dumps as part of recovery actions, or when the runtime error-checking value for the error disposition is ERROR_LIVE_DUMP. If you have root user authority, you can initiate live dumps when a subsystem does not respond or behaves erroneously. For more information about how to initiate and manage live dumps, see the livedumpstart and dumpctrl commands in AIX V6.1 command reference manuals, which are downloadable at the following site: http://publib.boulder.ibm.com/infocenter/pseries/v6r1/index.jsp Unlike system dumps, which are written to a dedicated dump device, live dumps are written to the file system. By default, live dumps are placed in the /var/adm/ras/livedump directory. The directory can be changed by using the dumpctrl command. In AIX V6.1, only serialized live dumps are available. A serialized live dump causes a system to be frozen or suspended when data is being dumped. The freeze is done by stopping all processors, except the processor running the dump. When the system is frozen, the data is copied to the live dump heap in pinned kernel memory. The data is then written to the file system, but only after the system is unfrozen. Live dump usually freezes the system for no more than 100 ms. The heapsz attribute (heap size) can be set to zero (0), meaning that at dump initialization time, the system calculates the live dump heap size based on the amount of real memory, which is the minimum of 16 MB or 1/64 the size of real memory (whichever is smaller). Duplicate live dumps that occur rapidly are eliminated to prevent system overload and to save file system space. Eliminating duplicate dumps requires periodic (once every 5 minutes) scans of the live dump repository through a cron job. Duplicate elimination can be stopped via the dumpctrl command. Each live dump has a data priority. A live dump of info priority is for informational purposes, and a live dump of critical priority is used to debug a problem. Info priority dumps can be deleted to make room for critical priority dumps. You can enable or disable all live dumps by using the dumpctrl ldmpon/ldmpoff command, or by using the SMIT fastpath: smitty livedump Note: Persistent options can be used to set state on further boots. 2.3.5 The dumpctrl command There is also the need to modify component, live, and system dump properties from one command. To achieve this, the dumpctrl command has been implemented in AIX V6.1. The dumpctrl command is used to query and modify global system and live dump properties, as well as per-component system and live dump properties, where appropriate. Note: Live dumps are compressed and must be uncompressed with the dmpumcompress command. 26 IBM AIX Continuous Availability Features
2.3.6 Parallel dump 2.3.7 Minidump An AIX system generates a system dump when a severe unrecoverable error occurs. System dumps can also be user-initiated by users with root user authority. A system dump creates a picture of your system's memory contents. However, systems have an increasingly large amount of memory and CPUs, and larger systems experience longer dump times. For this reason a new feature, parallel dump, was introduced in AIX V5.3 TL5. A new optimized compressed dump format has been introduced in AIX V5.3. The dump file extension for this new format is .BZ. In this new compressed dump file, the blocks are compressed and unordered; this unordered feature allows multiple processors to dump parallel sub-areas of the system. Parallel dumps are produced automatically when supported by the AIX release. Important: The new file format for parallel dump is not readable with uncompress and zcat commands. The new dmpuncompress command must be used instead. In order to increase dump reliability, a new -S checking option, to be used with the -L option for the statistical information on the most recent dump, is also added to the sysdumpdev command. The -S option scans a specific dump device and sees whether it contains a valid compressed dump. sysdumpdev -L -S The dump must be from an AIX release with parallel dump support. This flag can be used only with the -L flag. Additional options can be found and modified in SMIT via smitty dump. The minidump, introduced in AIX V5.3 TL3, is a small compressed dump that is stored to NVRAM when the system crashes or a dump is initiated, and is then written to the error log on reboot. It can be used to see some of the system state and do some debugging if a full dump is not available. It can also be used to obtain a quick snapshot of a crash without having to transfer the entire dump from the crashed system. Minidumps will show up as error log entries with a label of MINIDUMP_LOG and a description of COMPRESSED MINIMAL DUMP. To filter the minidump entries in the error log, you can use the errpt command with the –J flag (errpt [–a] –J MINIDUMP_LOG). Minidumps in the error log can be extracted, decompressed, and formatted using the mdmprpt command, as shown: mdmprpt [-l seq_no] [-i filename] [-r] More detailed information about minidump is available at the following site: http://igets3.fishkill.ibm.com/DCF/isg/isgintra.nsf/all/T1000676?OpenDocument&Highlight=0,m inidump 2.3.8 Trace (system trace) The AIX trace facility is a powerful system observation tool. The trace facility captures a sequential flow of time-stamped system events, thus providing a fine level of detail of system activity. Events are shown in time sequence and in the context of other events. Chapter 2. AIX continuous availability features 27
Page 1: Front cover IBM AIX Continuous Avai
Page 4 and 5: Note: Before using this information
Page 6 and 7: 2.3.7 Minidump . . . . . . . . . .
Page 8 and 9: vi IBM AIX Continuous Availability
Page 10 and 11: Trademarks The following terms are
Page 12 and 13: Engineering degree in Computer Scie
Page 14 and 15: Find out more about the residency p
Page 16 and 17: 1.1 Overview In May 2007, IBM intro
Page 18 and 19: 1.5 Continuous operations Continuou
Page 20 and 21: 1.6.2 Availability 1.6.3 Serviceabi
Page 22 and 23: IBM has tried to enhance FFDC featu
Page 24 and 25: 10 IBM AIX Continuous Availability
Page 26 and 27: 2.1 System availability AIX is buil
Page 28 and 29: On AIX 5.3, the only way to persist
Page 30 and 31: When used on a standalone server (s
Page 32 and 33: mirrored volume group on the client
Page 34 and 35: 2.2.1 Error checking Run-Time Error
Page 36 and 37: The PowerPC hardware gives software
Page 38 and 39: System dumps can also be user-initi
Page 42 and 43: Trace is a valuable tool for observ
Page 44 and 45: Component Trace uses mechanisms sim
Page 46 and 47: 2.3.14 syslog To display the boot l
Page 48 and 49: Logging can be added to many of the
Page 50 and 51: compression: on path specification:
Page 52 and 53: 2.4.4 EtherChannel network traffic
Page 54 and 55: 2.4.6 2-Port Adapter-based Ethernet
Page 56 and 57: operations) without affecting produ
Page 58 and 59: Quorum A quorum is a vote of the nu
Page 60 and 61: 2.5.8 Journaled File System-related
Page 62 and 63: Fast I/O failure is controlled by a
Page 64 and 65: display its output in a format suit
Page 66 and 67: For more detailed information about
Page 68 and 69: 54 IBM AIX Continuous Availability
Page 70 and 71: 3.1 AIX Reliability, Availability,
Page 72 and 73: This means that traditional AIX sys
Page 74 and 75: used by IBM service personnel, so t
Page 76 and 77: also be used to obtain a snapshot o
Page 78 and 79: 3.5 Live dump and component dump Li
Page 80 and 81: lfs filesystem ._0 | NO | ON/3 | OF
Page 82 and 83: .vmker | YES | ON/3 | OFF/3 .vmpool
Page 84 and 85: The output of Start a Live Dump is
Page 86 and 87: Table 3-3 Concurrent update termino
Page 88 and 89: We tested the installation of an ef
Page 90 and 91:
Setting efix state to: STABLE +----
Page 92 and 93:
mode, storage keys are called user
Page 94 and 95:
Example 3-19 shows the SMIT menu fo
Page 96 and 97:
might share a given hardware key. M
Page 98 and 99:
KKEY_UPUBLIC, KKEY_FILE_DATA KKEY_U
Page 100 and 101:
Note: Kernel keys and keysets, whic
Page 102 and 103:
extension key-aware is determining
Page 104 and 105:
added a protection gate for the int
Page 106 and 107:
} printf("hardware keyset after KER
Page 108 and 109:
} param=atoi(*(argv+1)); printf("Te
Page 110 and 111:
Load the kernel extension so that a
Page 112 and 113:
3 : 000000000000000A r4 : F10006C00
Page 114 and 115:
3.7.7 User mode protection keys Use
Page 116 and 117:
► The APIs provided by the system
Page 118 and 119:
if (!strcmp(*(argv+1),"read")){ if
Page 120 and 121:
strlen() at 0xd010da00 _doprnt(??,
Page 122 and 123:
int pthread_attr_setukeyset_np (pth
Page 124 and 125:
Machine State Save Area iar : 00000
Page 126 and 127:
As a consequence, determining the r
Page 128 and 129:
A Vue script or Vue program is a pr
Page 130 and 131:
► An optional predicate The predi
Page 132 and 133:
3. Interval probe manager The inter
Page 134 and 135:
{ int count; count = count +1; prin
Page 136 and 137:
► Errno names ► Signal names
Page 138 and 139:
* will result in error out of read(
Page 140 and 141:
This places a large part of the bur
Page 142 and 143:
Note: The frequency of checks made
Page 144 and 145:
Non-fragments 00000066 Promotions 0
Page 146 and 147:
immediately after the returned stor
Page 148 and 149:
This option should be used with car
Page 150 and 151:
3.9.6 KDB commands for XMDBG ► xm
Page 152 and 153:
138 IBM AIX Continuous Availability
Page 154 and 155:
Name AIX version Hardware required
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Online resources These Web sites ar
Page 162 and 163:
sysdumpdev 27 tprof 28 trace 28 trc
Page 164:
subsequent reboot 71, 133 SUE 18 Sy
show all

IBM AIX Continuous Availability Features - IBM Redbooks

Create successful ePaper yourself

Delete template?

Save as template?