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From Flavio Junqueira <fpjunque...@yahoo.com.INVALID>
Subject Re: Transaction logs and snapshots
Date Thu, 16 Apr 2015 20:29:23 GMT
Another think you could do is to make snapCount very large so that snapshots are created infrequently.
But, let me step back and ask you why you think ZK is a good fit for your project. It isn't
clear to me that your case is a good one for ZK.

-Flavio

 
> On 16 Apr 2015, at 11:01, Dejan Markic <Dejan.Markic@mobik-ics.com> wrote:
> 
> Hello!
> 
> Log seems to be always 67.108.880 bytes.
> Snapshots are currently between 30-40MB. Snapshot is created almost every minute.
> Yes, data durability is not important at all. Once the session ends (it may last between
0 and few minutes, average around 1-2 minutes maybe), I don't need it anymore. I regulary
remove  nodes that are not changed for more than 10 minutes.
> I even recieve updates for sessions, so even if ZK looses data, I would get it back after
few minutes.
> 
> Thanks!
> 
> Kind regards,
> Dejan
> 
> 
> -----Original Message-----
> From: Flavio Junqueira [mailto:fpjunqueira@yahoo.com.INVALID] 
> Sent: Thursday, April 16, 2015 11:49 AM
> To: user@zookeeper.apache.org
> Subject: Re: Transaction logs and snapshots
> 
> Hi Dejan,
> For a typical ZK application, granularity of hours is more than enough, since it is supposed
to be an infrequent background task. In your case, it sounds like durability isn't an important
property because if it is you shouldn't be getting rid of disk data this fast. I'm also wondering
about the amount of data you're generating. What's the size of your snapshots and txn logs?
> -Flavio 
> 
> 
>     On Thursday, April 16, 2015 10:26 AM, Dejan Markic <Dejan.Markic@mobik-ics.com>
wrote:
> 
> 
> 
> Hello Flavio!
> 
> Would that mean, that zkCleanup.sh would not be needed? 
> PurgeInterval is minimum 1 hour? Why is it so high?
> 
> Thanks!
> 
> Kind regards,
> Dejan Markic
> 
> 
> -----Original Message-----
> From: Flavio Junqueira [mailto:fpjunqueira@yahoo.com.INVALID] 
> Sent: Thursday, April 16, 2015 11:15 AM
> To: user@zookeeper.apache.org
> Subject: Re: Transaction logs and snapshots
> 
> Hi Dejan,
> Check if the autopurge feature solves your problem:
> http://zookeeper.apache.org/doc/r3.4.6/zookeeperAdmin.html#sc_advancedConfiguration
> 
> -Flavio 
> 
> 
>     On Thursday, April 16, 2015 9:17 AM, Dejan Markic <Dejan.Markic@mobik-ics.com>
wrote:
>   
> 
> 
> Hello all!
> 
> We are running 3 ZK servers in ensemble, and ZK is processing a lot of commands per seconds.
There are probably around 300 nodes created/checked/set/get per second.
> Since we have only information about live sessions we handle in ZK, we don't need any
data persistency - eg: we can stop all nodes, clean all transaction logs/snapshots, and start
them up again, without any issues.
> Since we have a lot of requests/changes, we have moved dataDir onto ramdisk, so we have
no problems with disk IOPS, etc.
> Is there a way, to minimze the usage of snapshots/logs so ramdisk would not get filled
up? It happens that transaction logs/snapshots grow so large, that we run out of space on
ramdisk.
> We issue >/usr/share/zookeeper/bin/zkCleanup.sh -n 3< every 2 minutes, so this
should cleanup the dataDir quite often. Why is >count number of snapshots/logs to keep<
limited to 3 and not below?
> I assume, in my setup, I don't even need snapshots/logs to be stored after they are not
actively needed? 
> So my basic questions are:
> - can I somehow get rid of snapshot/logs sooner, more often ... ?
> - when is snapshot created? Can it be created sooner, so it would be smaller? 
> - Is it possible to get rid of snapshot/logs all together?
> 
> Thank you for all your inputs and kind regards, Dejan Markic
> 
> 
>   
> 
> 
> 
> 


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