66. Can't view system log - fatal memory error

Million errors about your cache pool

Sep 28 17:45:30 Highlander kernel: BTRFS warning (device sdd1): lost page write due to IO error on /dev/sdf1
Sep 28 17:45:30 Highlander kernel: BTRFS error (device sdd1): error writing primary super block to device 3

 

I believe that error always happens when there are a lot of logged errors and the syslog gets very large, not sure if it's a bug or a design feature.

 

 

Edited September 29, 2018 by johnnie.black

Actually errors on multiple devices, and invalid parity. Are you already working on these problems on another thread?

One of his cache devices dropped offline, discussed here, parity is a difference issue I expect he's fixing on his own.

Yeah, parity is invalid as the cache problems @johnnie.black has been helping with have slowed down my whole array. 

By default Unraid reserves 128 MB for the log partition.

You can make a bigger reservation, e.g. I have the following in my 'go' file

# resize /var/log
mount -o remount,size=256m /var/log

 

I have the same memory problem, but not because of usual syslog errors. Its only I because I enabled the mover logs and use xfs defragmentation which adds a massive amount of debug lines to the log.

 

And this bug is not related to the size of /var/log. It's related to the PHP memory limit which is absolutely fine, but in /usr/local/emhttp/plugins/dynamix/include/Syslog.php this line is a problem:

foreach (file($log) as $line) {

This is a RAM killer as file() reads the complete log file into the RAM before executing further commands. It could be easily solved by replacing it against:

  $fh = fopen($log, "r");
  while (($line = fgets($fh)) !== false) {

Or even better (which limits the output to 1000 lines):

  $i=0;
  $line_count = intval(exec("wc -l '$log'"));
  $fh = fopen($log, "r");
  while (($line = fgets($fh)) !== false) {
    $i++;
    if ($i < $line_count - 1000) {
      continue;
    }

I tested this and now the RAM usage of my browser dropped by 1.6GB while viewing the syslog page and this is the first time I was able to open the syslogs through my smartphone which took ages before.

 

The fixed file:

Syslog.zip

 

EDIT: Ok, I found the file in the repository:

https://github.com/limetech/webgui/blob/master/plugins/dynamix/include/Syslog.php

 

Will try to fix it ^^

 

EDIT2: Yeah, my very first github pull request 😅

https://github.com/limetech/webgui/pull/770

 

Syslog.zip

Edited November 18, 2020 by mgutt

4 hours ago, mgutt said:

EDIT2: Yeah, my very first github pull request 😅

 

And hopefully not your last