syslog-ng-users July 2011 archive
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syslog-ng-users: Re: [syslog-ng] Trying to let my harddrive spin

Re: [syslog-ng] Trying to let my harddrive spin down once in a while

From: Lars Stokholm <lars.stokholm_at_nospam>
Date: Mon Jul 11 2011 - 17:40:15 GMT
To: "Syslog-ng users' and developers' mailing list" <syslog-ng@lists.balabit.hu>

Oh, I thought you wrote flush_lines. I don't have a flush_timeout in
my syslog-ng.conf. I see you set it in milliseconds. But what is the
default and what value would you recommend?

Lars

On Mon, Jul 11, 2011 at 7:21 PM, Paul Krizak <paul.krizak@amd.com> wrote:
> flush_timeout() and flush_lines() work together. Syslog-ng will write
> to disk if flush_lines() lines are in the buffer, *or* if
> flush_timeout() happens, whichever happens first.
>
> So to get your desired behavior you should set flush_timeout() to 60
> seconds or something, that way the 2-3 lines in the buffer will stay
> there long enough for the kernel to spin down the disks.
>
> Paul Krizak 7171 Southwest Pkwy MS B200.3A
> MTS Systems Engineer Austin, TX 78735
> Advanced Micro Devices Desk: (512) 602-8775
> Linux/Unix Systems Engineering Cell: (512) 791-0686
> Global IT Infrastructure Fax: (512) 602-0468
>
> On 07/11/2011 10:19 AM, Lars Stokholm wrote:
>> It's not silly and in fact I've set flush_lines (10); in
>> syslog-ng.conf. I know it's not a lot, but 10 lines is far more than
>> crond outputs per minute, which is why I don't understand syslog-ng
>> writes every minute when crond is running and almost not at all when
>> crond is not running. Am I making any sense? :)
>>
>> Lars
>>
>> On Mon, Jul 11, 2011 at 7:10 PM, Paul Krizak<paul.krizak@amd.com> wrote:
>>>
>>> This may be a silly question, but have you tried setting flush_timeout()
>>> to some large value so that messages are queued? Or is this not the
>>> behavior you seek? It seems fairly obvious to me that if you have
>>> anything writing to syslog at any time, and those messages end up in a
>>> file, that the kernel is going to spin up the disks and write out the
>>> dirty pages.
>>>
>>> The only way I can imagine to avoid this would be to queue the messages
>>> within syslog-ng (which won't cause any disk-backed pages in memory to
>>> become dirty) and only write them out at wide enough intervals that the
>>> kernel sees enough inactivity to spin down the disks.
>>>
>>> Paul Krizak 7171 Southwest Pkwy MS B200.3A
>>> MTS Systems Engineer Austin, TX 78735
>>> Advanced Micro Devices Desk: (512) 602-8775
>>> Linux/Unix Systems Engineering Cell: (512) 791-0686
>>> Global IT Infrastructure Fax: (512) 602-0468
>>>
>>> On 07/11/2011 09:58 AM, Lars Stokholm wrote:
>>>> Hello
>>>>
>>>> On my laptop I run Arch Linux with syslog-ng and cronie (cron) among
>>>> other programs of course.
>>>>
>>>> I'm trying to get my harddrive to spin down automatically once in a
>>>> while (using hdparm).
>>>>
>>>> Me and a lot of other people both in the Arch and Ubuntu community are
>>>> having our attempts to do this ruined, by what first seemed to be the
>>>> EXT4 journalling block device (jbd2).
>>>>
>>>> After long discussions and finally a bug report (see at the bottom of
>>>> this mail), I think I've boiled my troubles down to be mostly about
>>>> syslog-ng (and possibly cronie - but I don't think so).
>>>>
>>>> No matter what I try I can't seem to get syslog-ng to stop "waking up my
>>>> disks" (at least that's what kernel tracing tells me). Killing the crond
>>>> process almost totally stops these syslog-ng writes to the disk.
>>>> Unfortunately I've been unable to configure my way out of it using
>>>> syslog-ng.conf. So my harddrive won't stay spinned down - not even for a
>>>> minute.
>>>>
>>>> This is what tracing the journalling gives me (see the kernel bug report
>>>> below for an explanaition):
>>>> http://pastebin.com/raw.php?i=J6BtGVrz
>>>>
>>>> As you can probably see, syslog-ng writes every minute at least. I guess
>>>> that's because my user crontab has a command that gets run every minute.
>>>> What I don't get is why syslog-ng writes to the disk, even though I'm
>>>> telling it not to log crond's output.
>>>>
>>>> Here is my syslog-ng.conf - as you can see I tried to output the crond
>>>> messages to /dev/null. I guess it works, because there are no mentions
>>>> of crond anywhere in /var/log anymore.
>>>> http://pastebin.com/raw.php?i=H02KKWPV
>>>>
>>>> Here are the discussions and the bug report I mentioned:
>>>> https://bbs.archlinux.org/viewtopic.php?id=113516
>>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/607560
>>>> https://bugzilla.kernel.org/show_bug.cgi?id=39072
>>>>
>>>> I don't know if syslog-ng is causing trouble for only me, but it seems
>>>> unlikely.
>>>>
>>>> Regards,
>>>> Lars
>>>
>>> ______________________________________________________________________________
>>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>>> Documentation: http://www.balabit.com/support/documentation/?product=syslog-ng
>>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>>
>> ______________________________________________________________________________
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>> Documentation: http://www.balabit.com/support/documentation/?product=syslog-ng
>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>
>>
>
> ______________________________________________________________________________
> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
> Documentation: http://www.balabit.com/support/documentation/?product=syslog-ng
> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>
>
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