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--- linux:debug [2021/03/11 02:08]
tkilla created
+++ linux:debug [2021/05/03 13:18] (current)
tkilla [High Load]
@@ Line 1: / Line 1: @@
 ====== Debug ======
-Generic Tools to find root causes of problems
+Check the logs
   dmesg -Hw   # Human readable, follow
   tail -f /var/log/syslog
   tail -f /var/log/syslog
+===== Out of Memory Problems =====
 Check RAM usage. Yes, it's always full, but space in "buff/cache" is free to use
   free -m
+Show all Processes, sorted by virtual sizes (incl. shared libraries)
+  ps awwlx --sort=vsz
@@ Line 27: / Line 31: @@
-==== Tools to debug High Load ====
 === Check load ===
@@ Line 35: / Line 38: @@
   top
-  Cpu(s): 11.4%us, 29.6%sy, 0.0%ni, 58.3%id, .7%wa, 0.0%hi, 0.0%si, 0.0%st
+  sar -u 5
+Results: Cpu(s): 11.4%us, 29.6%sy, 0.0%ni, 58.3%id, .7%wa, 0.0%hi, 0.0%si, 0.0%st
 IF "wa" I/O wait is high, the load is most probably Disc bound (or RAM)
+IF "sy" System is high, it might be, **mdadm rund a RAID check**
@@ Line 52: / Line 60: @@
   ps -e v
-This outputs the state of each process. Specially D is intereting (but also R):
-D    Marks a process in disk (or other short term, uninterruptible) wait.
+Check which processes are in R or D state:
-R    Marks a runnable process
-...
+  ps -eo s,user,cmd | grep ^[RD] | sort | uniq -c | sort -nbr | head -20
+This outputs the state of each process. Specially D is interesting (but also R):
+  * D    Marks a process in disk (or other short term, uninterruptible) wait.
+  * R    Marks a runnable process
+PSN - Linux Process Snapper is another nice tool:
+Install from: https://tanelpoder.com/psnapper/
 === Links ===
   * https://www.linuxjournal.com/article/10688
-  *
+  * https://www.tummy.com/articles/isolating-heavy-load/
+  * https://tanelpoder.com/posts/high-system-load-low-cpu-utilization-on-linux/

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