Re: auditd and redhat cluster

On Tuesday, March 01, 2016 02:57:45 PM Maupertuis Philippe wrote: > The kernel is : 2.6.32-573.12.1.el6.x86_64 > And the whole audit.rules file is : <snip> > During the hour preceding the fence we got these events from the passive > node Key Summary Report > =========================== > total key > =========================== > 891 system_commands (ping) > > And on the active node : > > Key Summary Report > =========================== > total key > =========================== > 1330 system_commands > 286 deletion > > I am going to follow your advice and to open a call with redhat. > Anyway, I am interested in knowing if auditd has been reported to cause > trouble without generating many events. Those numbers work out to 27 events per minute. That's not really a lot of events. To see if its the rules or auditd causing the iowait, you might set the logging format to NOLOG. This will discard events rather than log them. If you still have iowait, its something to do with the rules. If that cleared it up, then auditd might be the source. Either way, put the format back to raw. I did some benchmarking of auditd over the holidays and posted some results here: https://www.redhat.com/archives/linux-audit/2015-December/msg00061.html I'd recommend: flush = incremental freq = 100 for a modest performance improvement. -Steve > -----Message d'origine----- > De : Paul Moore [mailto:paul@paul-moore.com] > Envoyé : mardi 1 mars 2016 14:25 > À : Maupertuis Philippe > Cc : linux-audit(a)redhat.com > Objet : Re: auditd and redhat cluster > > On Mon, Feb 29, 2016 at 7:45 AM, Maupertuis Philippe <philippe.maupertuis(a)worldline.com&gt; wrote: > > Hi list, > > > > One clusters fenced the passive node around two hours after auditd > > was started. > > > > We have found that iowait has increased since auditd was started and > > was unusually high. > > > > Auditd wasn’t generating many messages and there were no noticeable > > added activity on the disk were the audit and syslog files were written. > > > > Besides watches, the only general rules were : > > > > # creation > > -a exit,always -F arch=b32 -S creat -S mkdir -S mknod -S link -S > > symlink -S mkdirat -S mknodat -S linkat -S symlinkat -F uid=root -F > > success=1 -k creation -a exit,always -F arch=b64 -S creat -S mkdir -S > > mknod -S link -S symlink -S mkdirat -S mknodat -S linkat -S symlinkat > > -F uid=root -F success=1 -k creation > > > > # deletion > > -a exit,always -F arch=b32 -S rmdir -S unlink -S unlinkat -F uid=root > > -F > > success=1 -k deletion > > -a exit,always -F arch=b64 -S rmdir -S unlink -S unlinkat -F uid=root > > -F > > success=1 -k deletion > > > > After the rebot we deleted all rules and didn’t notice extra iowait > > anymore. > > > > Could these rules be the cause of additional iowait even if not > > generating many events (around 20 in two hours) ? > > > > Is there any other auditd mechanism that could explain this phenomenon ? > > > > I would appreciate any hints. > > Hi Philippe, > > First, as this is a RH cluster product, I would suggest contacting RH > support with your question if you haven't already; this list is primarily > for upstream development and support. > > If you are able to experiment with the system, or have a test environment, I > would suggest trying to narrow down the list of audit rules/watches to see > which rules/watches have the most affect on the iowait times. You've > listed four rules, but you didn't list the watches you have configured. > Also, what kernel version are you using? > > -- > paul moore > www.paul-moore.com > > !!!************************************************************************* > ************ "Ce message et les pièces jointes sont confidentiels et > réservés à l'usage exclusif de ses destinataires. Il peut également être > protégé par le secret professionnel. Si vous recevez ce message par erreur, > merci d'en avertir immédiatement l'expéditeur et de le détruire. > L'intégrité du message ne pouvant être assurée sur Internet, la > responsabilité de Worldline ne pourra être recherchée quant au contenu de > ce message. 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