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Posted to dev@zookeeper.apache.org by tobe <to...@gmail.com> on 2014/08/28 05:53:01 UTC
Why sessionTimeout is restricted by tickTime
Refer to the official guide, we know that the negotiationTimeout must be
greater than twice tickTime and smaller than 20 times of tickTime.
I know the tickTime should not be too large or even larger than
sessionTimeout, or the session will time out all the time. This limitation
is reasonable, but why the sessionTimeout must be smaller than 20 times of
tickTime?
The problem happens in our production environment. We share a ZooKeeper
cluster for a few HBase cluster. By default, the tickTime is 2s and the
sessionTimeout is 30s. It's ok. But now one of our HBase clusters need to
increase the sessionTimeout to 90s because of long time gc. After updating
the sessionTimout in HBase, we have to update the tickTime in ZooKeeper.
And this setting may have an effect on other HBase clusters.
So I wonder why ZooKeeper has this limitation. Can anyone explain to me?
Re: Why sessionTimeout is restricted by tickTime
Posted by tobe <to...@gmail.com>.
Thanks @Deng. I think I should set maxSessionTimeout rather than increasing
the tickTime. The default value of max session timeout is confusing and it
took us some time to notice this limitation. I will update the log to print
negotiationSessionTimeout rather than the sessionTimeout from client.
On Thu, Aug 28, 2014 at 12:35 PM, Hongchao Deng <fe...@hotmail.com>
wrote:
> My understanding is that large session timeout limits scalability of
> client numbers. Theoretically speaking, it is possible to increase the
> maximum session timeout in your case.
>
> - Hongchao Deng
>
>
> > Date: Thu, 28 Aug 2014 12:22:52 +0800
> > Subject: Re: Why sessionTimeout is restricted by tickTime
> > From: tobeg3oogle@gmail.com
> > To: user@zookeeper.apache.org
> > CC: dev@zookeeper.apache.org
>
> >
> > By the way, it comes down to a conflict if one ZooKeeper client set
> timeout
> > as 10 and one client set timeout as 110. The tickTime can't satisfy all.
> >
> >
> > On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
> >
> > > Refer to the official guide, we know that the negotiationTimeout must
> be
> > > greater than twice tickTime and smaller than 20 times of tickTime.
> > >
> > > I know the tickTime should not be too large or even larger than
> > > sessionTimeout, or the session will time out all the time. This
> limitation
> > > is reasonable, but why the sessionTimeout must be smaller than 20
> times of
> > > tickTime?
> > >
> > > The problem happens in our production environment. We share a ZooKeeper
> > > cluster for a few HBase cluster. By default, the tickTime is 2s and the
> > > sessionTimeout is 30s. It's ok. But now one of our HBase clusters need
> to
> > > increase the sessionTimeout to 90s because of long time gc. After
> updating
> > > the sessionTimout in HBase, we have to update the tickTime in
> ZooKeeper.
> > > And this setting may have an effect on other HBase clusters.
> > >
> > > So I wonder why ZooKeeper has this limitation. Can anyone explain to
> me?
> > >
>
Re: Why sessionTimeout is restricted by tickTime
Posted by tobe <to...@gmail.com>.
Thanks @Deng. I think I should set maxSessionTimeout rather than increasing
the tickTime. The default value of max session timeout is confusing and it
took us some time to notice this limitation. I will update the log to print
negotiationSessionTimeout rather than the sessionTimeout from client.
On Thu, Aug 28, 2014 at 12:35 PM, Hongchao Deng <fe...@hotmail.com>
wrote:
> My understanding is that large session timeout limits scalability of
> client numbers. Theoretically speaking, it is possible to increase the
> maximum session timeout in your case.
>
> - Hongchao Deng
>
>
> > Date: Thu, 28 Aug 2014 12:22:52 +0800
> > Subject: Re: Why sessionTimeout is restricted by tickTime
> > From: tobeg3oogle@gmail.com
> > To: user@zookeeper.apache.org
> > CC: dev@zookeeper.apache.org
>
> >
> > By the way, it comes down to a conflict if one ZooKeeper client set
> timeout
> > as 10 and one client set timeout as 110. The tickTime can't satisfy all.
> >
> >
> > On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
> >
> > > Refer to the official guide, we know that the negotiationTimeout must
> be
> > > greater than twice tickTime and smaller than 20 times of tickTime.
> > >
> > > I know the tickTime should not be too large or even larger than
> > > sessionTimeout, or the session will time out all the time. This
> limitation
> > > is reasonable, but why the sessionTimeout must be smaller than 20
> times of
> > > tickTime?
> > >
> > > The problem happens in our production environment. We share a ZooKeeper
> > > cluster for a few HBase cluster. By default, the tickTime is 2s and the
> > > sessionTimeout is 30s. It's ok. But now one of our HBase clusters need
> to
> > > increase the sessionTimeout to 90s because of long time gc. After
> updating
> > > the sessionTimout in HBase, we have to update the tickTime in
> ZooKeeper.
> > > And this setting may have an effect on other HBase clusters.
> > >
> > > So I wonder why ZooKeeper has this limitation. Can anyone explain to
> me?
> > >
>
RE: Why sessionTimeout is restricted by tickTime
Posted by Hongchao Deng <fe...@hotmail.com>.
My understanding is that large session timeout limits scalability of client numbers. Theoretically speaking, it is possible to increase the maximum session timeout in your case.
- Hongchao Deng
> Date: Thu, 28 Aug 2014 12:22:52 +0800
> Subject: Re: Why sessionTimeout is restricted by tickTime
> From: tobeg3oogle@gmail.com
> To: user@zookeeper.apache.org
> CC: dev@zookeeper.apache.org
>
> By the way, it comes down to a conflict if one ZooKeeper client set timeout
> as 10 and one client set timeout as 110. The tickTime can't satisfy all.
>
>
> On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
>
> > Refer to the official guide, we know that the negotiationTimeout must be
> > greater than twice tickTime and smaller than 20 times of tickTime.
> >
> > I know the tickTime should not be too large or even larger than
> > sessionTimeout, or the session will time out all the time. This limitation
> > is reasonable, but why the sessionTimeout must be smaller than 20 times of
> > tickTime?
> >
> > The problem happens in our production environment. We share a ZooKeeper
> > cluster for a few HBase cluster. By default, the tickTime is 2s and the
> > sessionTimeout is 30s. It's ok. But now one of our HBase clusters need to
> > increase the sessionTimeout to 90s because of long time gc. After updating
> > the sessionTimout in HBase, we have to update the tickTime in ZooKeeper.
> > And this setting may have an effect on other HBase clusters.
> >
> > So I wonder why ZooKeeper has this limitation. Can anyone explain to me?
> >
RE: Why sessionTimeout is restricted by tickTime
Posted by Hongchao Deng <fe...@hotmail.com>.
My understanding is that large session timeout limits scalability of client numbers. Theoretically speaking, it is possible to increase the maximum session timeout in your case.
- Hongchao Deng
> Date: Thu, 28 Aug 2014 12:22:52 +0800
> Subject: Re: Why sessionTimeout is restricted by tickTime
> From: tobeg3oogle@gmail.com
> To: user@zookeeper.apache.org
> CC: dev@zookeeper.apache.org
>
> By the way, it comes down to a conflict if one ZooKeeper client set timeout
> as 10 and one client set timeout as 110. The tickTime can't satisfy all.
>
>
> On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
>
> > Refer to the official guide, we know that the negotiationTimeout must be
> > greater than twice tickTime and smaller than 20 times of tickTime.
> >
> > I know the tickTime should not be too large or even larger than
> > sessionTimeout, or the session will time out all the time. This limitation
> > is reasonable, but why the sessionTimeout must be smaller than 20 times of
> > tickTime?
> >
> > The problem happens in our production environment. We share a ZooKeeper
> > cluster for a few HBase cluster. By default, the tickTime is 2s and the
> > sessionTimeout is 30s. It's ok. But now one of our HBase clusters need to
> > increase the sessionTimeout to 90s because of long time gc. After updating
> > the sessionTimout in HBase, we have to update the tickTime in ZooKeeper.
> > And this setting may have an effect on other HBase clusters.
> >
> > So I wonder why ZooKeeper has this limitation. Can anyone explain to me?
> >
Re: Why sessionTimeout is restricted by tickTime
Posted by tobe <to...@gmail.com>.
By the way, it comes down to a conflict if one ZooKeeper client set timeout
as 10 and one client set timeout as 110. The tickTime can't satisfy all.
On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
> Refer to the official guide, we know that the negotiationTimeout must be
> greater than twice tickTime and smaller than 20 times of tickTime.
>
> I know the tickTime should not be too large or even larger than
> sessionTimeout, or the session will time out all the time. This limitation
> is reasonable, but why the sessionTimeout must be smaller than 20 times of
> tickTime?
>
> The problem happens in our production environment. We share a ZooKeeper
> cluster for a few HBase cluster. By default, the tickTime is 2s and the
> sessionTimeout is 30s. It's ok. But now one of our HBase clusters need to
> increase the sessionTimeout to 90s because of long time gc. After updating
> the sessionTimout in HBase, we have to update the tickTime in ZooKeeper.
> And this setting may have an effect on other HBase clusters.
>
> So I wonder why ZooKeeper has this limitation. Can anyone explain to me?
>
Re: Why sessionTimeout is restricted by tickTime
Posted by tobe <to...@gmail.com>.
By the way, it comes down to a conflict if one ZooKeeper client set timeout
as 10 and one client set timeout as 110. The tickTime can't satisfy all.
On Thu, Aug 28, 2014 at 11:53 AM, tobe <to...@gmail.com> wrote:
> Refer to the official guide, we know that the negotiationTimeout must be
> greater than twice tickTime and smaller than 20 times of tickTime.
>
> I know the tickTime should not be too large or even larger than
> sessionTimeout, or the session will time out all the time. This limitation
> is reasonable, but why the sessionTimeout must be smaller than 20 times of
> tickTime?
>
> The problem happens in our production environment. We share a ZooKeeper
> cluster for a few HBase cluster. By default, the tickTime is 2s and the
> sessionTimeout is 30s. It's ok. But now one of our HBase clusters need to
> increase the sessionTimeout to 90s because of long time gc. After updating
> the sessionTimout in HBase, we have to update the tickTime in ZooKeeper.
> And this setting may have an effect on other HBase clusters.
>
> So I wonder why ZooKeeper has this limitation. Can anyone explain to me?
>