Diagnosing sudden increase in CPU usage (no images)
Hey everyone, Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl). No changes were made, updates nor configuration, and according to our monitoring started on the 23/03. Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%. Any ideas on where to start? Thanks in advance, Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
Hi Justin, there's some information missing from your message that could help a remote diagnosis: - Basic system information - Koha software information - Actions already taken, e.g. system restart, Koha restart, Plack restart Thanks! David Liddle System Administrator On Mon, Apr 20, 2026 at 6:39 AM Justin Dowswell via Koha < koha@lists.katipo.co.nz> wrote:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au _______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
Hi David, Sure thing, apologies! Koha 24.11.14 (I updated to this in the last couple of weeks hoping there was a bugfix) on Debian Bookworm LTS, shipped with the 6.1.159 kernel (linux-support-6.1.0-42). The issue persists on reboot. On Mon, 20 Apr 2026 at 17:00, David Liddle <david_liddle@sil.org> wrote:
Hi Justin, there's some information missing from your message that could help a remote diagnosis: - Basic system information - Koha software information - Actions already taken, e.g. system restart, Koha restart, Plack restart
Thanks!
David Liddle System Administrator
On Mon, Apr 20, 2026 at 6:39 AM Justin Dowswell via Koha < koha@lists.katipo.co.nz> wrote:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
_______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
Running 10.11.14-MariaDB, Apache/2.4.66, perl 5 version 36 - unsure if these are useful or whether this perl version is an assumed dependency version of the Koha version. Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au On Mon, 20 Apr 2026 at 17:37, Justin Dowswell < justin.dowswell@tenantsunion.org.au> wrote:
Hi David,
Sure thing, apologies!
Koha 24.11.14 (I updated to this in the last couple of weeks hoping there was a bugfix) on Debian Bookworm LTS, shipped with the 6.1.159 kernel (linux-support-6.1.0-42).
The issue persists on reboot.
On Mon, 20 Apr 2026 at 17:00, David Liddle <david_liddle@sil.org> wrote:
Hi Justin, there's some information missing from your message that could help a remote diagnosis: - Basic system information - Koha software information - Actions already taken, e.g. system restart, Koha restart, Plack restart
Thanks!
David Liddle System Administrator
On Mon, Apr 20, 2026 at 6:39 AM Justin Dowswell via Koha < koha@lists.katipo.co.nz> wrote:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
_______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
Hi everyone, Just following up on this. Would be good to know who I could reach out for some paid support regarding this, if this is deemed more appropriate. Thanks in advance, Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au On Mon, 20 Apr 2026 at 17:46, Justin Dowswell < justin.dowswell@tenantsunion.org.au> wrote:
Running 10.11.14-MariaDB, Apache/2.4.66, perl 5 version 36 - unsure if these are useful or whether this perl version is an assumed dependency version of the Koha version.
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
On Mon, 20 Apr 2026 at 17:37, Justin Dowswell < justin.dowswell@tenantsunion.org.au> wrote:
Hi David,
Sure thing, apologies!
Koha 24.11.14 (I updated to this in the last couple of weeks hoping there was a bugfix) on Debian Bookworm LTS, shipped with the 6.1.159 kernel (linux-support-6.1.0-42).
The issue persists on reboot.
On Mon, 20 Apr 2026 at 17:00, David Liddle <david_liddle@sil.org> wrote:
Hi Justin, there's some information missing from your message that could help a remote diagnosis: - Basic system information - Koha software information - Actions already taken, e.g. system restart, Koha restart, Plack restart
Thanks!
David Liddle System Administrator
On Mon, Apr 20, 2026 at 6:39 AM Justin Dowswell via Koha < koha@lists.katipo.co.nz> wrote:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
_______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
Kia ora! Not sure what is appropriate or not, but there is a list of support providers on the Community website. It has three listings for Australia: https://koha-community.org/support/paid-support/country/#aus As it says on the page: "This directory and its contents, including but not limited to the links to other sites, purveyors, providers, and vendors of other goods, services, or information, whether for informational purposes or in the form of paid advertisement, are made available by the Koha community on an “as is” basis and without any warranties of any kind as to accuracy, merchantability, or fitness of a vendor for a particular service. Restricting your choice of provider only to ones included on the list may unfairly exclude support providers and consultants who provide services for mainstream Koha. Inclusion on this directory implies no “official” status whatsoever. Any organization who claims to be an “official” Koha support provider is misrepresenting their relationship to the Koha project." :-) Best regards, Magnus Enger Libriotech AS Den 30.04.2026 04:55, skrev Justin Dowswell via Koha:
Hi everyone,
Just following up on this.
Would be good to know who I could reach out for some paid support regarding this, if this is deemed more appropriate.
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
On Mon, 20 Apr 2026 at 17:46, Justin Dowswell < justin.dowswell@tenantsunion.org.au> wrote:
Running 10.11.14-MariaDB, Apache/2.4.66, perl 5 version 36 - unsure if these are useful or whether this perl version is an assumed dependency version of the Koha version.
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
On Mon, 20 Apr 2026 at 17:37, Justin Dowswell < justin.dowswell@tenantsunion.org.au> wrote:
Hi David,
Sure thing, apologies!
Koha 24.11.14 (I updated to this in the last couple of weeks hoping there was a bugfix) on Debian Bookworm LTS, shipped with the 6.1.159 kernel (linux-support-6.1.0-42).
The issue persists on reboot.
On Mon, 20 Apr 2026 at 17:00, David Liddle <david_liddle@sil.org> wrote:
Hi Justin, there's some information missing from your message that could help a remote diagnosis: - Basic system information - Koha software information - Actions already taken, e.g. system restart, Koha restart, Plack restart
Thanks!
David Liddle System Administrator
On Mon, Apr 20, 2026 at 6:39 AM Justin Dowswell via Koha < koha@lists.katipo.co.nz> wrote:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au
_______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
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Hi Justin Do you see many seraches by AI bots in your Placks log? tail -f /var/log/koha/$YOURINSTANCE/plack.log Best wishes: Michael -- Geschäftsführer · Diplombibliothekar BBS, Informatiker eidg. Fachausweis Admin Kuhn GmbH · Pappelstrasse 20 · 4123 Allschwil · Schweiz T 0041 (0)61 261 55 61 · E mik@adminkuhn.ch · W www.adminkuhn.ch Am 20.04.26 um 06:38 schrieb Justin Dowswell via Koha:
Hey everyone,
Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl).
No changes were made, updates nor configuration, and according to our monitoring started on the 23/03.
Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%.
Any ideas on where to start?
Thanks in advance,
Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au _______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
Indeed, word-wild AI bots are scrapping Koha OPACs. The main performance issue if opac-search.pl. You may look at apache acces logs to check some IP geolocalisation. IF they come from several countries and use odd user-agents (we found some IE6 and Windows 98) it might be AI bots. Best regards. Le 20/04/2026 à 09:13, Michael Kuhn via Koha a écrit :
Hi Justin
Do you see many seraches by AI bots in your Placks log?
tail -f /var/log/koha/$YOURINSTANCE/plack.log
Best wishes: Michael
-- Fridolin SOMERS <fridolin.somers@biblibre.com> Software and system maintainer 🦄 BibLibre, France
Justin, I think Michael Kuhn's and Fridolin Somers' suggestions to analyze the web traffic are your best next step. Do you also: - have a *robots.txt* file, and/or - have the recent *antibot* feature (see Bug 39906 <https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=39906>) activated? If you don't have much experience reading and interpreting web logs, you may find that something like GoAccess <https://goaccess.io/> can help you get a quick summary. On Mon, Apr 20, 2026 at 10:13 AM Fridolin SOMERS via Koha < koha@lists.katipo.co.nz> wrote:
Indeed, word-wild AI bots are scrapping Koha OPACs. The main performance issue if opac-search.pl.
You may look at apache acces logs to check some IP geolocalisation. IF they come from several countries and use odd user-agents (we found some IE6 and Windows 98) it might be AI bots.
Best regards.
Le 20/04/2026 à 09:13, Michael Kuhn via Koha a écrit :
Hi Justin
Do you see many seraches by AI bots in your Placks log?
tail -f /var/log/koha/$YOURINSTANCE/plack.log
Best wishes: Michael
-- Fridolin SOMERS <fridolin.somers@biblibre.com> Software and system maintainer 🦄 BibLibre, France
_______________________________________________
Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha
participants (5)
-
David Liddle -
Fridolin SOMERS -
Justin Dowswell -
Magnus Enger -
Michael Kuhn