DHCP restart with bulk lease data

[Surya Teja]

I was thinking that since it leaves the .<time> file present, it may have
problems doing the file operations.
I did some experimenting, whatever way I make the files write protected,
dhcpd manages to change them back. The only thing I did not test is SELinux.
-------> Sten, can you suggest few steps to cross check on how to confirm
that would be file operations issues when it has bulk data

On Tue, Oct 29, 2019 at 7:11 PM Sten Carlsen <stenc at s-carlsen.dk> wrote:

>
>
>
> On 29 Oct 2019, at 13.49, Surya Teja <suryateja042 at gmail.com> wrote:
>
> Could there be issues with file permissions?
> My guess is that the temporary file written can not be renamed because
> dhcpd does not have write permissions?   ------>
> Hi Sten, I don't think it is with permission because after few minutes
> dhcpd is restarting and granting lease, the issue is it is taking long time,
>
>
> I was thinking that since it leaves the .<time> file present, it may have
> problems doing the file operations.
> I did some experimenting, whatever way I make the files write protected,
> dhcpd manages to change them back. The only thing I did not test is SELinux.
>
> In the isc dhcp forum I observed few options like  dont-use-fsync but it
> also suggest not recommended until thorough understanding OS
> I have installed the dhcpd on centos7, does any one have used this option?
> Any experience with it would be much helpful for me
>
> Thanks in advance
>
> On Tue, Oct 29, 2019 at 6:12 PM Surya Teja <suryateja042 at gmail.com> wrote:
>
>> you're doing something wrong. With a decent disk subsystem this is
>> expected to take a few *seconds* (5 - 10 seconds would be my estimate )
>> ---->
>> Hi  sthaug I don't see any disk subsystem issues, may be I am missing the
>> cases, can you please suggest the areas or commands to cross check if
>> possible?
>>
>>
>> Thanks Teja
>>
>> On Tue, Oct 29, 2019 at 5:13 PM Sten Carlsen <stenc at s-carlsen.dk> wrote:
>>
>>>
>>>
>>> > On 29 Oct 2019, at 11.20, sthaug at nethelp.no wrote:
>>> >
>>> >> The main thing I am facing the issue is when the data is too high like
>>> >> 50-60k leases in the file, the dhcpd service restart is taking more
>>> time
>>> >> (nearly 5-6 minutes) some times nearly 10-11 mins
>>> >
>>> > If a dhcpd restart with 50 - 60k leases takes 5-6 minutes or more,
>>> > you're doing something wrong. With a decent disk subsystem this is
>>> > expected to take a few *seconds* (5 - 10 seconds would be my estimate
>>> > based on what we see here with a larger leases file).
>>>
>>> Could there be issues with file permissions?
>>>
>>> My guess is that the temporary file written can not be renamed because
>>> dhcpd does not have write permissions?
>>>
>>> >
>>> > Steinar Haug, Nethelp consulting, sthaug at nethelp.no
>>> > _______________________________________________
>>> > dhcp-users mailing list
>>> > dhcp-users at lists.isc.org
>>> > https://lists.isc.org/mailman/listinfo/dhcp-users
>>>
>>>
>
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