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Zookeeper, mail # dev - RE: [jira] [Commented] (ZOOKEEPER-866) Adding no disk persistence option in zookeeper.


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Re: [jira] [Commented] (ZOOKEEPER-866) Adding no disk persistence option in zookeeper.
Ted Dunning 2012-11-21, 22:18
+1

But of course the speedups are large enough that it is pretty clear that
this will make a significant difference almost regardless of size.

On Wed, Nov 21, 2012 at 12:26 PM, Dayal Dilli <[EMAIL PROTECTED]>wrote:

> hi Graham,
>
> Could you please update with some more details like the size of znode
> created and some of the system parameters like size of the ramdisk, size of
> RAM etc.. I guess this would give a better idea to compare your results
> with ours and discuss on improvements.
>
> ________________________________________
> From: Graham (JIRA) [[EMAIL PROTECTED]]
> Sent: Wednesday, November 21, 2012 2:57 PM
> To: [EMAIL PROTECTED]
> Subject: [jira] [Commented] (ZOOKEEPER-866) Adding no disk persistence
> option in zookeeper.
>
>     [
> https://issues.apache.org/jira/browse/ZOOKEEPER-866?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13502200#comment-13502200]
>
> Graham commented on ZOOKEEPER-866:
> ----------------------------------
>
> We ran some benchmarks using zk-latencies.
>
> We tried to ways to boost performance: Using a RAM disk (tmpfs) and using
> libeatmydata (Makes all file system sync operations no-ops).
>
> libeatmydata benchmarks: http://pastebin.com/cNLjfhPG
>
> Ramdisk using tmpfs benchmarks: http://pastebin.com/mfe92nXn (Note:
> Different box to the last one)
>
> In summary: Synchronous calls are boosted by two orders of magnitude with
> either libeatmydata or ramdisk (In Standalone mode and also clustered
> mode). Asynchronous calls are boosted by a factor of 2 or 3.
>
> For tests, simulations etc. a Zookeeper without snapshots or logs makes a
> lot of sense, but for production use, the ramdisk or eatmydata options both
> looks pretty good.
>
> Another thing we found works well is to have a battery backed raid array;
> writes to go to raid cache and will sync to disk eventually.
>
>
>
> > Adding no disk persistence option in zookeeper.
> > -----------------------------------------------
> >
> >                 Key: ZOOKEEPER-866
> >                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-866
> >             Project: ZooKeeper
> >          Issue Type: New Feature
> >            Reporter: Mahadev konar
> >            Assignee: Mahadev konar
> >             Fix For: 3.5.0
> >
> >         Attachments: ZOOKEEPER-nodisk.patch
> >
> >
> > Its been seen that some folks would like to use zookeeper for very fine
> grained locking. Also, in there use case they are fine with loosing all old
> zookeeper state if they reboot zookeeper or zookeeper goes down. The use
> case is more of a runtime locking wherein forgetting the state of locks is
> acceptable in case of a zookeeper reboot. Not logging to disk allows high
> throughput on and low latency on the writes to zookeeper. This would be a
> configuration option to set (ofcourse the default would be logging to disk).
>
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