I have seen in various threads on the list that 3.0.x is probably best for
prod. Just wondering though if there is anything in particular in 3.7 to be
weary of.

I need to check with one of our QA engineers to get specifics on the
storage. Here is what I do know. We have a blade center running lots of
virtual machines for various testing. Some of those vm's are running
Cassandra and the Java web apps I previously mentioned via docker
containers. The storage is shared. Beyond that I don't have any more
specific details at the moment. I can also tell you that the storage can be
quite slow.

I have come across different threads that talk to one degree or another
about the flush queue getting full. I have been looking at the code in
ColumnFamilyStore.java. Is perDiskFlushExecutors the thread pool I should
be interested in? It uses an unbounded queue, so I am not really sure what
it means for it to get full. Is there anything I can check or look for to
see if writes are getting blocked?

On Tue, Sep 20, 2016 at 8:41 PM, Jonathan Haddad <j...@jonhaddad.com> wrote:

> If you haven't yet deployed to prod I strongly recommend *not* using 3.7.
> What network storage are you using?  Outside of a handful of highly
> experienced experts using EBS in very specific ways, it usually ends in
> failure.
> On Tue, Sep 20, 2016 at 3:30 PM John Sanda <john.sa...@gmail.com> wrote:
>> I am deploying multiple Java web apps that connect to a Cassandra 3.7
>> instance. Each app creates its own schema at start up. One of the schema
>> changes involves dropping a table. I am seeing frequent client-side
>> timeouts reported by the DataStax driver after the DROP TABLE statement is
>> executed. I don't see this behavior in all environments. I do see it
>> consistently in a QA environment in which Cassandra is running in docker
>> with network storage, so writes are pretty slow from the get go. In my logs
>> I see a lot of tables getting flushed, which I guess are all of the dirty
>> column families in the respective commit log segment. Then I seen a whole
>> bunch of flushes getting queued up. Can I reach a point in which too many
>> table flushes get queued such that writes would be blocked?
>> --
>> - John


- John

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