RE: Question on 11gR2 RAC Cluster Time Synchronization Service (CTSS)
- From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
- To: Li Li <litanli@xxxxxxxxx>, Martin Klier <usn@xxxxxxxxx>
- Date: Thu, 23 Jun 2011 10:01:05 +0200
Li,
Why not use the ntp deamon instead of ntpdate with cron?
When using the "-x" option (on linux) you also don't have the risk that your
clock will be set back in time, which can cause node reboots (at least in 10g).
Below you find the configuration I use for ntp (on linux):
/etc/ntp.conf
-------------
# Prohibit general access to this service
restrict default ignore
# Permit all access over the loopback interface.
restrict 127.0.0.1
# --- OUR TIMESERVERS -----
# or remove the default restrict line
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
server <ntp servername 1>
restrict <ntp server ip 1> mask 255.255.255.255 nomodify notrap noquery
server <ntp servername 2>
restrict <ntp server ip 2> mask 255.255.255.255 nomodify notrap noquery
# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available.
server 127.127.1.0
fudge 127.127.1.0 stratum 10
# Drift file. Put this in a directory which the daemon can write to.
# No symbolic links allowed, either, since the daemon updates the file
# by creating a temporary in the same directory and then rename()'ing
# it to the file.
driftfile /var/lib/ntp/drift
/etc/ntp/step-tickers
----------------------
<ntp server ip 1>
<ntp server ip 2>
/etc/sysconfig/ntpd
--------------------
# Drop root to id 'ntp:ntp' by default.
OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid -x"
# Set to 'yes' to sync hw clock after successful ntpdate
SYNC_HWCLOCK=no
# Additional options for ntpdate
NTPDATE_OPTIONS=""
chkconfig --list ntpd
----------------------
ntpd 0:off 1:off 2:on 3:on 4:on 5:on 6:off
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer
-----Original Message-----
From: Li Li [mailto:litanli@xxxxxxxxx]
Sent: donderdag 23 juni 2011 0:09
To: Martin Klier
Cc: D'Hooge Freek; oracle-l
Subject: Re: Question on 11gR2 RAC Cluster Time Synchronization Service (CTSS)
Thanks Freek and Martin for you reply!
We have been using ntpdate for time sync in a cron job in our 10gR2
RAC, guess we'll still need to use it in 11gR2 RAC. I wonder why
Oracle provides CTSS since we still need to sync time with a time
server?
On Wed, Jun 22, 2011 at 11:30 AM, Martin Klier <usn@xxxxxxxxx> wrote:
> Hi together,
>
> I have the same problem, and I solved it with a carefully adjusted drift
> file (using ntpdate from time to time)
>
> Regards
> Martin
>
> D'Hooge Freek schrieb:
>> Li,
>>
>> CTTS will indeed only keep the time of the cluster nodes synchronised
>> between the nodes themselves and not with an external source.
>> If you want this, then you need to configure the network time protocol (NTP)
>> daemon.
>> When the NTPD is running, the CTTS process will automatically run in
>> "observer" mode.
>>
>>
>> Regards,
>>
>> Freek D'Hooge
>> Uptime
>> Oracle Database Administrator
>> email: freek.dhooge@xxxxxxxxx
>> tel +32(0)3 451 23 82
>> http://www.uptime.be
>> disclaimer: www.uptime.be/disclaimer
>>
>> -----Original Message-----
>> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
>> On Behalf Of Li Li
>> Sent: woensdag 22 juni 2011 17:17
>> To: oracle-l
>> Subject: Question on 11gR2 RAC Cluster Time Synchronization Service (CTSS)
>>
>> Hi, List,
>>
>> In a 11.2.0.2 RAC, with 11gR2 RAC Cluster Time Synchronization Service
>> (CTSS) running in active mode, CTSS does its work to sync time among
>> all nodes in the cluster. However, the time on all nodes gets behind
>> after a while (say 5 minutes behind after 8 months) . How would you
>> guys handle this situation? and how would you prevent this from
>> happening again? I've googled and searched on oracle documentation and
>> couldn't find anything about it.
>>
>> Thanks in advance!
>> -Li
>> --
>> //www.freelists.org/webpage/oracle-l
>>
>>
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>>
>
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