I checked the code handling the IGNITE_HOME and persistent storage paths,
and here is what the algorithm looks like.
For IGNITE_HOME the following is checked in order; if on any step a value is
found then we use it.
- IgniteHome in IgniteConfiguration
- IGNITE_HOME system property
- IGNITE_HOME environment variable
- Current working directory (user.dir) and all its ancestors (all directories
are checked to have “bin/” and “config/”)
- Class path entry containing ignite-core classes and all its ancestors
After that, the working directory will be created at one of the following paths
- WorkingDirectory in IgniteConfiguration, if set
- ${IGNITE_HOME}/work, if IGNITE_HOME could be calculated previously
- ${java.io.tmpdir}/work
Persistent storage will be stored in the working directory, unless StoragePath
are specified in the config
(same for WAL and WalPath).
The issue here is that if we’ve ended up having persistent DB in the working
directory in the /tmp,
then persistence files will be cleared upon restart.
Also, IgniteConfiguration::getIgniteHome claims that Igntie fails if
IGNITE_HOME is not set, but that’s not the case.
So, how about actually disallowing to run Ignite when IGNITE_HOME can’t be
calculated? Using /tmp for working
directory seems to be an obscure and potentially harmful scenario.
IgniteConfiguration’s documentation can also be adjusted to specify actual
steps used to find IgniteHome and WorkingDirectory
if they aren’t set explicitly.
Additionally, I’d suggest not to promote setting IGNITE_HOME system property
and environment variable
(e.g. let’s remove it from readmeio). IgniteConfiguration seems to be the most
straightforward way to configure Ignite,
and system properties should be used as a backup plan when convenient.
WDYT?
Thanks,
Stan
From: Denis Magda
Sent: 30 января 2018 г. 3:38
To: dev@ignite.apache.org
Subject: Re: IGNITE_HOME for persistence
No we don’t. I’ve never touched IGNITE_HOME variable for any other purpose.
As it was suggested, the reported should share the project to reproduce his
scenario.
—
Denis
> On Jan 26, 2018, at 9:05 PM, Dmitriy Setrakyan <d...@gridgain.com> wrote:
>
> Igniters,
>
> I have just stumbled upon this post on SO:
> https://stackoverflow.com/questions/48434929/apache-ignite-persistent-storage
>
> Do we require IGNITE_HOME to be set if the persistence is enabled? If yes,
> do we check for it on startup?
>
> D.
