All
Accepted answers
Mikhail Khomenko · Nov 7, 2016 go to post

Lisa and Kate, at first thanks for your answers!

[root@ecp01 log]# cat /etc/iscagent/iscagent.conf
mirroring.console_logging_enabled=true

 

I can't see any changes either in /var/log/messages nor in /var/log/iscagent_console.log with or without this line. I have a feeling that this parameter won't work. Example of session:

 

[root@ecp01 log]# cat /etc/iscagent/iscagent.conf
mirroring.console_logging_enabled=true
[root@ecp01 log]# systemctl stop ISCAgent
[root@ecp01 log]# systemctl start ISCAgent
[root@ecp01 log]# /usr/local/etc/cachesys/ISCAgentCtrl status
application_server.interface_address=*
application_server.port=2188
daemonized=yes
mirroring=on
pid=2591
running=yes
version=2016.2.0.721.0
 

This parameter is absent in status output.

What about the reason of such interest. Initially I've tried to understand why in Linux with systemd (RHEL 7.2, for example) Backup Failover member (connected to Arbiter) can't takes over Primary when I power off Primary server (additional condition: both Failover members were started by 'ccontrol start' ). There is a WRC 870617. 

But now it's just a interest for better understanding of switching processes.

Mikhail Khomenko · Nov 5, 2016 go to post

Aaron, thanks for answer! But, yes, why are exactly 8 daemons? Why not 4 or 13? Is there a method to configure it ($zu or cstat, or smth else)? As I've read somewhere, a few daemons appear because Linux didn't support async IO. Is this still true? It would be great to clarify the exact role of the Main Daemon and Slave Daemons. What I already noticed that these daemons wake up every 10 seconds to check write daemon queue. I think this one is the general for all of them. It would be cool to get more information about their configuration.

Mikhail Khomenko · Nov 2, 2016 go to post

Lisa, thanks for your answer!
I add this string to iscagent.conf, restart ISCAgent but at the first glance can't  see a difference in log file:

Nov  2 12:37:32 localhost ISCAgent[2796]: Starting
Nov  2 12:37:32 localhost ISCAgent[2796]: ISCAgent starting up
Nov  2 12:37:32 localhost ISCAgent[2796]: Application server enabled.
Nov  2 12:37:32 localhost ISCAgent[2797]: Starting ApplicationServer on *:2188

 

And no new messages when Primary and Backup connected to Arbiter. Just old messages:

Nov  2 12:45:08 localhost ISCAgent[2856]: Serving application: ISC1ARBITER
Nov  2 12:45:24 localhost ISCAgent[2858]: Serving application: ISC1ARBITER

 

Maybe, I'm doing something wrong )
Thanks!

Mikhail Khomenko · Nov 1, 2016 go to post

Hi, Alexey! Thanks for you answer!

But I'm not completely agree with it. My laptop has one physical drive /dev/sda and two logical volumes above it (home + root) plus /boot on /dev/sda1.  And I've met different production server disk configurations with the same 7 SWDs. Additionally, how we can comment the file descriptors opened by those 7 SWDs + 1 WD?

[root@HP-6360B ~]# for wd in `pgrep -f WD`;do ls -l /proc/$wd/fd | grep -v '/dev/null';done
total 0
l-wx------ 1 root root 64 Nov  1 08:09 3 -> /opt/intersystems/cache-2016.2/bin/clock
lrwx------ 1 root root 64 Nov  1 08:09 4 -> /opt/intersystems/cache-2016.2/mgr/CACHE.WIJ
lrwx------ 1 root root 64 Nov  1 08:09 5 -> /opt/intersystems/cache-2016.2/mgr/CACHE.DAT
lrwx------ 1 root root 64 Nov  1 08:09 6 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
lrwx------ 1 root root 64 Nov  1 08:09 7 -> /opt/intersystems/cache-2016.2/mgr/cacheaudit/CACHE.DAT
lrwx------ 1 root root 64 Nov  1 08:09 8 -> /opt/intersystems/cache-2016.2/mgr/cache/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:09 3 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
total 0
lrwx------ 1 root root 64 Nov  1 08:10 3 -> /opt/intersystems/cache-2016.2/mgr/cachetemp/CACHE.DAT
 

 

Some of WDs has opened CACHESYS, some  - CACHETEMP as well as the main WD which doesn't have to write to disk at all (I've met such statement).

Mikhail Khomenko · Oct 30, 2016 go to post

I've found messages from ISCAgent in /var/log/messages. Something like this:

Oct 30 07:26:04 ecp01 ISCAgent[3823]: ISCAgent starting up
Oct 30 07:26:04 ecp01 ISCAgent[3823]: Application server enabled.
Oct 30 07:26:04 ecp01 ISCAgent[3824]: Starting ApplicationServer on *:2188

And I've found in docs that ISCAgent uses syslog system. So I can add to /etc/rsyslog.conf file the next string:

if $programname == 'ISCAgent' then /var/log/iscagent_console.log

Than restart rsyslog. And we get the same messages in iscagent_console.log.

That's fine. The more interesting are messages like this:

Oct 30 07:26:53 ecp01 ISCAgent[3550]: Arbiter client error: Message read failed.

 

This message appears on system with arbiter when Primary Failover member is halted by reboot or 'init 0' command. I would be glad to know what this message means. So this was the reason of question about ISCAgent debugging.

 

Thanks!

Mikhail Khomenko · May 13, 2016 go to post

Thank you, Ray! Something like this I've supposed. Ok, we'll be more careful in the future.