As far as I remember, last webinar I heard on Ignite Native Persistence
- it actually exposes some interfaces like IgniteWriteAheadLogManager,
PageStore, PageStoreManager, etc., with the file-based implementation
provided by Ignite being only one possible approach, and users can
create their own Native Persistence variations. At least that what has
been said by Denis Magda at that time.
May be creating own implementation of Ignite Native Persistence rather
than CacheStore based persistence is an option here?
On 11/23/2017 2:23 AM, Valentin Kulichenko wrote:
Vyacheslav,
There is no way to do this and I'm not sure why you want to do this. Ignite
persistence was developed to solve exactly the problems you're describing.
Just use it :)
-Val
On Wed, Nov 22, 2017 at 12:36 AM, Vyacheslav Daradur <daradu...@gmail.com>
wrote:
Valentin, Evgeniy thanks for your help!
Valentin, unfortunately, you are right.
I've tested that behavior in the following scenario:
1. Started N nodes and filled it with data
2. Shutdown one node
3. Called rebalance directly and waited to finish
4. Stopped all other (N-1) nodes
5. Started N-1 nodes and validated data
Validation didn't pass - data consistency was broken. As you say it
works only on stable topology.
As far as I understand Ignite doesn't manage to rebalance in
underlying storage, it became clear from tests and your description
that CacheStore design assumes that the underlying storage is shared
by all the
nodes in the topology.
I understand that PDS is the best option in case of distributing
persistence.
However, could you point me the best way to override default rebalance
behavior?
Maybe it's possible to extend it by a custom plugin?
On Wed, Nov 22, 2017 at 1:35 AM, Valentin Kulichenko
<valentin.kuliche...@gmail.com> wrote:
Vyacheslav,
If you want the persistence storage to be *distributed*, then using
Ignite
persistence would be the easiest thing to do anyway, even if you don't
need
all its features.
CacheStore indeed can be updated from different nodes with different
nodes,
but the problem is in coordination. If instances of the store are not
aware
of each other, it's really hard to handle all rebalancing cases. Such
solution will work only on stable topology.
Having said that, if you can have one instance of RocksDB (or any other
DB
for that matter) that is accessed via network by all nodes, then it's
also
an option. But in this case storage is not distributed.
-Val
On Tue, Nov 21, 2017 at 4:37 AM, Vyacheslav Daradur <daradu...@gmail.com
wrote:
Valentin,
Why don't you use Ignite persistence [1]?
I have a use case for one of the projects that need the RAM on disk
replication only. All PDS features aren't needed.
During the first assessment, persist to RocksDB works faster.
CacheStore design assumes that the underlying storage is shared by
all
the nodes in topology.
This is the very important note.
I'm a bit confused because I've thought that each node in cluster
persists partitions for which the node is either primary or backup
like in PDS.
My RocksDB implementation supports working with one DB instance which
shared by all the nodes in the topology, but it would make no sense of
using embedded fast storage.
Is there any link to a detailed description of CacheStorage design or
any other advice?
Thanks in advance.
On Fri, Nov 17, 2017 at 9:07 PM, Valentin Kulichenko
<valentin.kuliche...@gmail.com> wrote:
Vyacheslav,
CacheStore design assumes that the underlying storage is shared by all
the
nodes in topology. Even if you delay rebalancing on node stop (which
is
possible via CacheConfiguration#rebalanceDelay), I doubt it will
solve
all
your consistency issues.
Why don't you use Ignite persistence [1]?
[1] https://apacheignite.readme.io/docs/distributed-persistent-store
-Val
On Fri, Nov 17, 2017 at 4:24 AM, Vyacheslav Daradur <
daradu...@gmail.com
wrote:
Hi Andrey! Thank you for answering.
Key to partition mapping shouldn't depends on topology, and
shouldn't
changed unstable topology.
Key to partition mapping doesn't depend on topology in my test
affinity function. It only depends on partitions number.
But partition to node mapping depends on topology and at cluster
stop,
when one node left topology, some partitions may be moved to other
nodes.
Does all nodes share same RockDB database or each node has its own
copy?
Each Ignite node has own RocksDB instance.
Would you please share configuration?
It's pretty simple:
IgniteConfiguration cfg = new IgniteConfiguration();
cfg.setIgniteInstanceName(instanceName);
CacheConfiguration<Integer, String> cacheCfg = new
CacheConfiguration<>();
cacheCfg.setName(TEST_CACHE_NAME);
cacheCfg.setCacheMode(CacheMode.PARTITIONED);
cacheCfg.setWriteSynchronizationMode(
CacheWriteSynchronizationMode.PRIMARY_SYNC);
cacheCfg.setBackups(1);
cacheCfg.setAffinity(new
TestAffinityFunction(partitionsNumber, backupsNumber));
cacheCfg.setWriteThrough(true);
cacheCfg.setReadThrough(true);
cacheCfg.setRebalanceMode(CacheRebalanceMode.SYNC);
cacheCfg.setCacheStoreFactory(new
RocksDBCacheStoreFactory<>("/test/path/to/persistence",
TEST_CACHE_NAME, cfg));
cfg.setCacheConfiguration(cacheCfg);
Could you give me advice on places which I need to pay attention?
On Wed, Nov 15, 2017 at 3:02 PM, Andrey Mashenkov
<andrey.mashen...@gmail.com> wrote:
Hi Vyacheslav,
Key to partition mapping shouldn't depends on topology, and
shouldn't
changed unstable topology.
Looks like you've missed smth.
Would you please share configuration?
Does all nodes share same RockDB database or each node has its own
copy?
On Wed, Nov 15, 2017 at 12:22 AM, Vyacheslav Daradur <
daradu...@gmail.com>
wrote:
Hi, Igniters!
I’m using partitioned Ignite cache with RocksDB as 3rd party
persistence
store.
I've got an issue: if cache rebalancing is switched on, then it’s
possible to lose some data.
Basic scenario:
1) Start Ignite cluster and fill a cache with RocksDB persistence;
2) Stop all nodes
3) Start Ignite cluster and validate data
This works fine while rebalancing is switched off.
If rebalancing switched on: when I call Ignition#stopAll, some
nodes
go down sequentially and while one node having gone down another
start
rebalancing. When nodes started affinity function works with a
full
set of nodes and may define a wrong partition for a key because
the
previous state was changed at rebalancing.
Maybe I'm doing something wrong. How can I avoid rebalancing while
stopping all nodes in the cluster?
Could you give me any advice, please?
--
Best Regards, Vyacheslav D.
--
Best regards,
Andrey V. Mashenkov
--
Best Regards, Vyacheslav D.
--
Best Regards, Vyacheslav D.
--
Best Regards, Vyacheslav D.
