Crash Dump Analysis Patterns (Part 62)
DATA (Dump Analysis + Trace Analysis) Facebook group
Please join the community of memory (dump) and trace analysis engineers. This group promotes scientific methods and memory dump-based world view.
Twitter @ DumpAnalysis You can now follow portal and blog news at DumpAnalysis on Twitter.
2009 (0x7D9) - The Year of Debugging 2010 (0x7DA) - The Year of Dump Analysis 2011 (0x7DB) - 2020 (0x7E4) The Debugging Decade
Software ageing can be the cause of the problem. Sometimes a look at the following WinDbg output can give irresistible temptation to suggest periodic reboots:
Debug session time: Wed April 28 15:36:52.330 2008 (GMT+0)
System Uptime: 124 days 6:27:16.658
The suggested pattern name is Overaged System.
- Dmitry Vostokov @ DumpAnalysis.org -
_1125.png)
Coming Soon:
Crash Dump Analysis for System Administrators
New Magazines:
Debugged! MZ/PE: MagaZine for/from Practicing Engineers
New Books:
Windows Debugging: Practical Foundations
DLL List Landscape: The Art from Computer Memory Space
Dumps, Bugs and Debugging Forensics: The Adventures of Dr. Debugalov
WinDbg: A Reference Poster and Learning Cards
Memory Dump Analysis Anthology, Volume 2
Also available:
Memory Dump Analysis Anthology, Volume 1
New Children's Book:
May 29th, 2008 at 6:34 pm
Hello,
Following is what happened one of our overaged servers. Virtual Memory Address fragmentation seems inevitable even if we’re using LFH (Low Fragmentation Heap). This machine have had plenty of free physical memory but we had to restart the service.
Usually large Uncommitted Ranges are bad but in this case 200 UCR caused 98% Virtual Address Fragmentation though which is a little bit strange.
0:020> !heap -s
Heap Flags Reserv Commit Virt Free List UCR Virt Lock Fast
(k) (k) (k) (k) length blocks cont. heap
—————————————————————————–
006c0000 00001002 2565820 7232 658924 1302 160 200 0 44f3b4 LFH
External fragmentation 18 % (160 free blocks)
Virtual address fragmentation 98 % (200 uncommited ranges)
July 29th, 2008 at 7:22 pm
[…] to Overaged System sometimes we can see Young System pattern. This means that the system didn’t have time to […]