IBM AIX Continuous Availability Features - IBM Redbooks

More documents

Recommendations

Info

Non-fragments 00000066 Promotions 00000200 Page Promotion Frag size Frequency [00010] 00000200 [00020] 00000200 [00040] 00000200 [00080] 00000200 [00100] 00000200 [00200] 00000200 [00400] 00000200 [00800] 00000200 [01000] 00000200 [02000] 00000200 [04000] 00000200 [08000] 00000200 Ratio of memory to declare a memory leak: 0x400(1024)/0x400(1024) Outstanding memory allocations to declare a memory leak: -1 Deferred page reclamation count (-1 == when necessary): 16384 Minimum allocation size to force a record for: 1048576 Maximal error checking level At maximal error checking level, all tunables are set at maximum levels (level 9). Performance is greatly affected at this checking level. All the frequencies should match the frequency base, meaning all checks are always done. It is set by executing: errctrl -c alloc.xmdbg errchecklevel=9 Example 3-48 shows frequencies for various tunables of alloc.xmdbg at the highest RTEC level. Example 3-48 Frequencies for xmalloc at maximal level (0)> xm -Q XMDBG data structure @ 00000000025426F0 Debug State: Enabled Frequency Base: 00000400 Tunable Frequency Allocation Record 00000400 Ruin All Data 00000400 Trailer non-fragments 00000400 Trailer in fragments 00000400 Redzone Page 00000400 VMM Check 00000400 Deferred Free Settings Fragments 00000400 Non-fragments 00000400 Promotions 00000400 Page Promotion Frag size Frequency [00010] 00000400 [00020] 00000400 [00040] 00000400 [00080] 00000400 [00100] 00000400 [00200] 00000400 [00400] 00000400 130 IBM AIX Continuous Availability Features
[00800] 00000400 [01000] 00000400 [02000] 00000400 [04000] 00000400 [08000] 00000400 Ratio of memory to declare a memory leak: 0x400(1024)/0x400(1024) Outstanding memory allocations to declare a memory leak: -1 Deferred page reclamation count (-1 == when necessary): 16384 Minimum allocation size to force a record for: 1048576 Note: The bosdebug -M command sets all the frequencies for alloc.xmdbg at maximal level except for “promotion settings” which are all set to zero (0). A reboot is required in order for bosdebug to take effect. 3.9.4 XMDBG tunables affected by error check level As previously mentioned, xmalloc RTEC features are activated for a given allocation based on probabilities. The errctrl command that controls the tunables takes the probability of application (frequency) as an argument. In AIX V6.1, the user can set the probability of a check being performed by specifying the frequency of a tunable as a number between 0 and 1024. This is the number of times out of the base frequency (1024) that the technique is to be applied by xmalloc. For example, to request 50%, the user specifies a frequency of 512. Frequencies can be input as decimal or hex numbers, so 50% can be specified as 0x200. As a convenient alternative, the frequency can be expressed as a percentage. To do this, the user specifies a number between 0 and 100 followed by the percent (%) sign. The following sections detail the RTEC tunables for the xmalloc.xmdbg component. Keep an allocation record This option sets the frequency of keeping a record for an allocation. Records are also kept if any other debug technique is applied, so the percentage of allocations with a record may be considerably larger than this number would otherwise indicate. The allocation record contains a three-level stack trace-back of the xmalloc() and xmfree() callers, as well as other debug information about the allocated memory. The presence of a record is a minimum requirement for xmalloc run time error checking. errctrl -c alloc.xmdbg alloc_record= Ruin storage This option sets the frequency at which xmalloc() will return storage that is filled with a “ruin” pattern. This helps catch errors with un-initialized storage, because a caller with bugs is more likely to crash when using the ruined storage. Note that xmalloc() does not perform any explicit checks when this technique is employed. The ruined data will contain 0x66 in every allocated byte on allocation, and 0x77 in every previously allocated byte after being freed. errctrl -c alloc.xmdbg ruin_all= Check for overwrites in small allocations This is one of the three options that affect the frequency of trailers. There are two options that deal with trailers, and a third option deals with compatibility with previous versions of AIX. This option is specific for allocations that are less than half a page. A trailer is written Chapter 3. AIX advanced continuous availability tools and features 131
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 40 and 41:
Live dumps are small dumps that do
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 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 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?