Bug 1331857

Summary: Invalid system activity file: /var/log/sysstat/sa* generated after changing number of CPUs on a virtual machine
Product: Red Hat Enterprise Linux 6 Reporter: Marc Richter <mrichter>
Component: sysstatAssignee: Peter Schiffer <pschiffe>
Status: CLOSED WONTFIX QA Contact: BaseOS QE - Apps <qe-baseos-apps>
Severity: low Docs Contact:
Priority: low    
Version: 6.7   
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2016-04-30 09:49:30 UTC Type: Bug
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Marc Richter 2016-04-29 20:10:30 UTC 
Description of problem: After changing the number of virtual CPUs on a VM, the current sar data file becomes corrupt and unusable.


Version-Release number of selected component (if applicable):

sysstat-9.0.4-27.el6.x86_64

How reproducible: using a RHEL 6.7 KVM hosted VM. Customer was using VMware


Steps to Reproduce:
1. Fire up a RHEL 6.7 VM
2. Check that sar is producing good output. Let the system run for a few collection cycles
3. Increase the number of CPUs. If system won't hotplug, reboot it.
4. Issue a sar command and the error message will result

Actual results: error


Expected results: sar data goodness


Additional info:
Comment 2 Peter Schiffer 2016-04-29 21:49:12 UTC 
Marc,

changing the number of CPUs within one sa data file is supported since sysstat 10.3.1. Here are the commits from the upstream:

https://github.com/sysstat/sysstat/commit/8a2b558892353ff1fdcc70be187106837aeea882
https://github.com/sysstat/sysstat/commit/cd31adf53381b6fa88b145a7e608bc83f0f454b4
https://github.com/sysstat/sysstat/commit/372339579ff08e92610303c3b96276f65faa5f51
https://github.com/sysstat/sysstat/commit/f4878ad79941bec3674946a9bb4ac921b8cec46e
https://github.com/sysstat/sysstat/commit/cd625e9cad4acf03d0dda0059af337f70b90036b
https://github.com/sysstat/sysstat/commit/331c3f97ad71fc86b6878c3412a20b7d25d7dd07

From the commits you can see that this is a huge change, and what is more, this change breaks backward compatibility of the sa data files, what disallow us to backport this feature to the RHEL-6. Unfortunately, RHEL-7 ships with sysstat 10.1.5, so it won't work there either..

peter
Comment 3 Marc Richter 2016-04-30 01:28:48 UTC 
Peter,

So what I'm hearing is "Yeah, not a chance." ;-)

No worries, I think this is a real edge case and not worth the risk of even arguing a backport.

We can close this as WONTFIX if necessary.

Marc
Comment 4 Peter Schiffer 2016-04-30 09:49:30 UTC 
Thanks Marc.