[Users] Problem in 3.3 with shmmax configuration

[Sandro Bonazzola]

Il 05/11/2013 15:13, Bob Doolittle ha scritto:
> 
> On 11/05/2013 02:13 AM, Sandro Bonazzola wrote:
>> Il 04/11/2013 17:17, Bob Doolittle ha scritto:
>>> On 11/04/2013 05:43 AM, Sandro Bonazzola wrote:
>>>> Il 02/11/2013 17:51, Bob Doolittle ha scritto:
>>>>> Hi,
>>>>>
>>>>> I'm setting up Engine for the 2nd time - the first time I answered a configuration question wrong. So I did:
>>>>>
>>>>> engine-setup
>>>>> engine-cleanup
>>>>> engine-setup
>>>>>
>>>>> Things worked, until I rebooted the system. I found that postgresql would not startup, and was failing with "could not create shared memory segment:
>>>>> Invalid Argument".
>>>>>
>>>>> I resolved this issue by creating a file /etc/sysctl.d/10-shmmax.conf, containing the line:
>>>>> kernel.shmmax = 1000000000
>>>>>
>>>>> (I read somewhere that postgresql recommends setting shmmax to 1/4 of physical memory, and I have 4GB)
>>>>>
>>>>> 1. Is this a known bug? If not, should I file one? If so, how do I do that? :)
>>>> Which version are you installing?
>>> 3.3, on Fedora 19.
>>>
>>>> Can you please attach all 3 logs from above sequence (setup, cleanup, setup)?
>>>> I think something may have gone wrong on second setup execution while setting shmmax.
>>> Unfortunately I no longer have those logs.
>>>
>>> *However* last night I powered down my node and engine. Last night engine would at least come up.
>>>
>>> Now when I boot up my engine I get the same error. So my guess is that the shmmax setting isn't being configured in a persistent fashion somehow, or
>>> is somehow reverting.
>>>
>>> My most recent setup log is here (I hate to send large logs to lists):
>>> https://dl.dropboxusercontent.com/u/35965416/ovirt-engine-setup-20131103141618.log
>> 2013-11-03 14:18:18 DEBUG otopi.plugins.ovirt_engine_setup.system.sysctl plugin.execute:441 execute-output: ('/sbin/sysctl', '-n', 'kernel.shmmax')
>> stdout:
>> 35554432
>>
>> setup detected that your shmmax is already configured with a good value so it didn't change the configuration.
>> If you set above value before running setup, please retry running setup without setting it or setting it to a value less than 35554432.
>> setup will detect it's too low and will create needed configuration files for fixing it.
> 
> 
> Except that when the system booted postgresql failed to come up because it failed to allocate the shm segment it wanted, and when I checked
> /proc/sys/kernel/shmmax the value was much lower than that. I have again set the value in syscfg and things are working now.
> 
> So my guess is that something is reverting the value after engine-setup has set it, or else somehow it was not set in a persistent fashion by
> engine-setup. Where is the shmmax value stored by engine-setup? Should there be a file in /etc/syscfg.d? There was not.

the file created by engine-setup is /etc/sysctl.d/ovirt-engine.conf.
Note that the file is created by engine-setup only if shmmax is < 35554432 when it's running.

You can run # sysctl --system and see which files are loaded:

# sysctl --system
* Applying /usr/lib/sysctl.d/00-system.conf ...
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
* Applying /usr/lib/sysctl.d/libvirtd.conf ...
fs.aio-max-nr = 1048576
* Applying /usr/lib/sysctl.d/nepomuk-inotify.conf ...
fs.inotify.max_user_watches = 524288
* Applying /etc/sysctl.d/ovirt-engine.conf ...
kernel.shmmax = 35554432
* Applying /etc/sysctl.conf ...



> 
> -Bob
> 


-- 
Sandro Bonazzola
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