# rw\_err\_ack\_nomatch errors

**URL:** <https://discuss.aerospike.com/t/rw-err-ack-nomatch-errors/1502>\
**Category:** Monitoring\
**Created:** [July 16, 2015, 3:08pm UTC](https://discuss.aerospike.com/t/rw-err-ack-nomatch-errors/1502 "2015-07-16T15:08:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ashishbhutani](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.aerospike.com/ashishbhutani/32/183_2.png) [@ashishbhutani](https://discuss.aerospike.com/u/ashishbhutani)\
**Post date:** [July 16, 2015, 3:08pm UTC](https://discuss.aerospike.com/t/rw-err-ack-nomatch-errors/1502/1 "2015-07-16T15:08:56Z")

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Hi

We are monitoring our Aerospike cluster through metrics(collectd plugin) and see ‘rw\_err\_ack\_nomatch’ errors frequently.

Metrics docs suggest that it’s “Number of prole write acknowledgments started but went amiss/have mismatched information”.

The meaning is not clear to me. I have replication factor of 3. Does this mean that while writing, it couldn’t be successfully written to replicas ?

Does this indicate write loss or just acks or any inconsistency between master and replica nodes ? Does it point to flaky network or some problem in my config ? Should I be worried about it? Also, All my err\_write\* metrics have zero values.

Can someone please help in clarifying about this metrics and should I be worried about this metrics ? Thanks!

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<div class="post-metadata">

**Author:** ![ashishbhutani](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.aerospike.com/ashishbhutani/32/183_2.png) [@ashishbhutani](https://discuss.aerospike.com/u/ashishbhutani)\
**Post date:** [July 21, 2015, 5:25pm UTC](https://discuss.aerospike.com/t/rw-err-ack-nomatch-errors/1502/2 "2015-07-21T17:25:22Z")

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Any pointers on understanding about this metrics shall be helpful 😄I am regularly getting these errors. Thanks!

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<div class="post-metadata">

**Author:** ![wchu](https://avatars.discourse-cdn.com/v4/letter/w/a5b964/32.png) [@wchu](https://discuss.aerospike.com/u/wchu)\
**Post date:** [July 22, 2015, 3:25am UTC](https://discuss.aerospike.com/t/rw-err-ack-nomatch-errors/1502/3 "2015-07-22T03:25:09Z")

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The counter increases when a replica finishes work, acknowledge the master that it has finished, but realizes the transaction has already finished.

The case where this happens is that there is a retry message sent from master to the replicas - replica will receive the message 2 times, and both times will acknowledge back to master. First time, master completes the transaction. Second time, the counter will increase, and the ack will be ignored.

This is not a big concern. If it really happens very often, then you may want to look into why master wants to retry very often (default setting is 1 second).