# Mixing WiredTiger & Percona Memory Engine

**URL:** <https://forums.percona.com/t/mixing-wiredtiger-percona-memory-engine/5432>\
**Category:** Percona Server for MongoDB\
**Created:** [February 23, 2017, 11:50am UTC](https://forums.percona.com/t/mixing-wiredtiger-percona-memory-engine/5432 "2017-02-23T11:50:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![leeus](https://avatars.discourse-cdn.com/v4/letter/l/a183cd/32.png) [@leeus](https://forums.percona.com/u/leeus)\
**Post date:** [February 23, 2017, 11:50am UTC](https://forums.percona.com/t/mixing-wiredtiger-percona-memory-engine/5432/1 "2017-02-23T11:50:06Z")

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I have just installed Percona 3.4 and see that the Memory Engine is a really nice option. Is is possible to use WiredTiger for one database and Memory Engine for another? I can’t work out how if so!!

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**Author:** ![david.murphy](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/david.murphy/32/16877_2.png) [@david.murphy](https://forums.percona.com/u/david.murphy)\
**Post date:** [February 23, 2017, 11:57am UTC](https://forums.percona.com/t/mixing-wiredtiger-percona-memory-engine/5432/2 "2017-02-23T11:57:10Z")

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Hi leeus,

Unfortunately, the MongoDB storage API is designed so only one engine may be active at a time. One thing maybe people do is have different shards for different workloads, as each replica-set could have a different engine they use. This is something we are looking at the possibility of changing but I do not know a timeline or probability of that feature just yet.

Cheers  
David Murphy

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**Author:** ![leeus](https://avatars.discourse-cdn.com/v4/letter/l/a183cd/32.png) [@leeus](https://forums.percona.com/u/leeus)\
**Post date:** [February 28, 2017, 2:01am UTC](https://forums.percona.com/t/mixing-wiredtiger-percona-memory-engine/5432/3 "2017-02-28T02:01:44Z")

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Thanks David. I think I will have a few shards based on the workload.

Lee