Hey Mason - and others
Are there any other "first rules" we may have missed?
Many thanks,
Agnes
On 06/03/2012 6:06 PM, Mason James wrote:
On 2012-03-7, at 7:05 AM, Agnes Rivers-Moore wrote:
Hello Mason
Thank you for your thoughtful comments on my problems.
I will pass them on to Petrus who set up the Xen stuff.
As the list was broken for a few days we had time to discover a couple of
contributing factors.
One was the Gnome GUI - not loading properly at start-up.
Another was vino - VNC which is reported in Ubuntu forums as grabbing 100% CPU
under some conditions.
Running with Gnome turned off in the virtual server where the problem seems to
originate has resulted in two peaceful days. It is too soon to be sure but ...
seems to be at least a major contributor.
Agnes
aaaaah, yep... ;)
the first rule of running production linux servers is *dont* install a gui on
it (gnome, kde etc)
especially on your VMs!
(if you dont have a gui on your server... you also have no reason to vnc to
your server)
give your sysadmin a slap! ;)
On 06/03/2012 2:48 AM, Mason James wrote:
On 2012-02-29, at 1:00 PM, Agnes Rivers-Moore wrote:
Dear friends
We have six libraries running Koha 3.00.06.
The system runs Redhat, with 6 virtual Xen servers.
i also run some Koha systems on xen (debian-squeeze)
Problem #1
From time to time, at various times of day one or more of the Koha systems
will slow down and stop.
install nagios, munin and monit on your systems, to help determine what is
causing the slowdown
We can watch the CPU graph on the virtual machine manager - it usually drops
to less than 1% use for a few minutes.
At this point we have librarians staring at unresponsive Koha screens -
connecting... connecting...
The virtual server desktop is unresponsive even at the physical server.
hmmm... that sounds like a general xen problem, not a Koha problem
is your system running out of resources (RAM or swap)?
We cannot connect with a VNC client or browse in.
This is very frustrating when the CPU graph implies that the server is
apparently not busy.
Then the CPU use will ramp rapidly up to 12.4% use (which is pretty much full
capacity on our virtual server setup).
It stays there - and although it may have recovered once or twice from this,
usually we have to kill the server.
Sometimes we force the VM to shut down, and then restart it, and can see zebra
searches happening with Top. However we may still be unable to log in with VNC
or connect from local client browsers.
This is really difficult to track down because we have not found associated
error messages, and by the time we get to them, the servers seem to be showing
low load, but we may be missing some initiating event.
That is problem #1
Here is problem #2
We have also noticed that opac-search.pl and mysqld is causing heavy loading.
Within the virtual server we have multiple cpus and the load is shared between
them,
However, often opac-search.pl is around 30%, and mysqld alone is using close to
half of the virtual server's CPU capacity.
The records we have in this single site library do not have large numbers of
items attached to any one biblio record.
There was a discussion in March about something like this a year ago, but I
can't see a resolution.
Does anyone have any ideas on either of these issues?
Hoping someone from the developer group might have some ideas.
are you clearing you cookies and sessions tables periodically? they might be
getting really big
there is a script about for that task
also, run 'SHOW PROCESSLIST' in mysql to discover what mysql is doing when it's
thrashing
i recommend running a single mysqld process on the dom-0,
rather than a mysqld process on each of your 6 dom-u's
cheers, Mason
--
CEO/ Chief Librarian
Hanover Public Library.
451 10th Ave,
Hanover, ON
N4N 2P1
Tel: 519-364-1420
Email: [email protected]
Please consider the environment before printing this message or attachments.
Support your library! Please consider making a donation, joining the Friends of
the Library, or remembering us in your will.
cheers, Mason
--
CEO/ Chief Librarian
Hanover Public Library.
451 10th Ave,
Hanover, ON
N4N 2P1
Tel: 519-364-1420
Email: [email protected]
Please consider the environment before printing this message or attachments.
Support your library! Please consider making a donation, joining the Friends of
the Library, or remembering us in your will.
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