how to access same dbd file from different voldemort server concurrently

[Dileep Shetty]

Hi,

we are using 2 instance of voldemort servers which is having /data common. Now When one server is using /data/bdb file another cannot able to write it to same file. and It will give below exception.

Please help on this. 

Exception in thread "main" voldemort.store.StorageInitializationException: com.sleepycat.je.EnvironmentLockedException: (JE 4.0.92) /voldemort/data/bdb The environment cannot be locked for single writer access. ENV_LOCKED: The je.lck file could not be locked. Environment is invalid and must be closed.

        at voldemort.store.bdb.BdbStorageConfiguration.getStore(BdbStorageConfiguration.java:129)

        at voldemort.server.storage.StorageService.startInner(StorageService.java:203)

        at voldemort.server.AbstractService.start(AbstractService.java:62)

        at voldemort.server.VoldemortServer.startInner(VoldemortServer.java:213)

        at voldemort.server.AbstractService.start(AbstractService.java:62)

        at voldemort.server.VoldemortServer.main(VoldemortServer.java:260)

Caused by: com.sleepycat.je.EnvironmentLockedException: (JE 4.0.92) /voldemord/data/bdb The environment cannot be locked for single writer access. ENV_LOCKED: The je.lck file could not be locked. Environment is invalid and must be closed.

[Arunachalam]

Embedded databases does not work this way.  What are you trying to do ?

http://docs.oracle.com/cd/E17275_01/html/programmer_reference/cam.html

Thanks,

Arun.

--
You received this message because you are subscribed to the Google Groups "project-voldemort" group.
To unsubscribe from this group and stop receiving emails from it, send an email to project-voldem...@googlegroups.com.
Visit this group at http://groups.google.com/group/project-voldemort.
For more options, visit https://groups.google.com/d/optout.

[Dileep Shetty]

Hi arun,

I want to store the voldemort data at one place and all other voldemort servers should access it (read/write concurrently). Its like Database where multiple application can read and write simultaneously. Can voldemort work in that way? Is there any properties we can set it, so that no voldemort server should lock the data (/data/dbd files) and all other voldemort instances can read/write into to it?

[Brendan Harris (a.k.a. stotch on irc.oftc.net)]

Hi Dileep,

On Sunday, April 12, 2015 at 2:50:35 AM UTC-7, Dileep Shetty wrote:

I want to store the voldemort data at one place and all other voldemort servers should access it (read/write concurrently). Its like Database where multiple application can read and write simultaneously. Can voldemort work in that way? Is there any properties we can set it, so that no voldemort server should lock the data (/data/dbd files) and all other voldemort instances can read/write into to it?

No, none of the voldemort storage engines support this. I am not aware of any database server that supports this, not in a read/write fashion anyway. I suppose you could write your own storage engine for voldemort to do this, but you'd have to be very careful with the multithreaded semantics of this and use some form of a system-wide IPC lock. And there's no demand for this kind of methodology in a storage engine, so you're not going to find a lot of products out there that support this.

Brendan

 

[Arunachalam]

Then your only option I believe is MySQL. But Voldemort is never tested with production workload on MySQL, I am not aware of any one using it extensively. 

Embedded databases are totally different concepts than the normal database. Any basic article will explain the difference and the trade offs they make.

Thanks,

Arun.

--

[Arunachalam]

Also, you are telling what you want to achieve and not what you want. Why do you want to spin up multiple instances of Voldemort, why not have one serve all ? If you can tell us what is your end goal, we can guide you or we can tell whether Voldemort is the right technology for you.

Thanks,

Arun.