Re: Is it safe to change RF in this situation?

Thanks a lot. Will do as you suggested. On Thu, Sep 8, 2016 at 3:08 PM, Hannu Kröger wrote: > Ok, so I have to say that I’m not 100% sure how many replicas of data is > it trying to maintain but it should not blow up (if repair crashes or > something, it’s ok). So it should

Re: Is it safe to change RF in this situation?

Ok, so I have to say that I’m not 100% sure how many replicas of data is it trying to maintain but it should not blow up (if repair crashes or something, it’s ok). So it should be safe to do. When the repair has run you can start with the plan I suggested and run repairs afterwards. Hannu >

Re: Is it safe to change RF in this situation?

Thanks. What about this situation: * Change RF 2 => 3 * Start repair * Roll back RF 3 => 2 * repair is still running I'm wondering what the repair is trying to do? The repair is trying to fix as RF=2 or still trying to fix like RF=3? On Thu, Sep 8, 2016 at 2:53 PM, Hannu Kröger

Re: Is it safe to change RF in this situation?

Yep, you can fix it by running repair or even faster by changing the consistency level to local_quorum and deploying the new version of the app. Hannu > On 8 Sep 2016, at 17:51, Benyi Wang wrote: > > Thanks Hannu, > > Unfortunately, we started changing RF from 2 to 3,

Re: Is it safe to change RF in this situation?

Thanks Hannu, Unfortunately, we started changing RF from 2 to 3, and did see the empty result rate is going higher. I assume that "If the LOCAL_ONE read hit the new replica which is not there yet, the CQL query will return nothing." Is my assumption correct? On Thu, Sep 8, 2016 at 11:49 AM,

Re: Is it safe to change RF in this situation?

Hi, If you change RF=2 -> 3 first, the LOCAL_ONE reads might hit the new replica which is not there yet. So I would change LOCAL_ONE -> LOCAL_QUORUM first and then change the RF and then run the repair. LOCAL_QUORUM is effectively ALL in your case (RF=2) if you have just one DC, so you can

Is it safe to change RF in this situation?

* I have a keyspace with RF=2; * The client read the table using LOCAL_ONE; * There is a batch job loading data into the tables using ALL. I want to change RF to 3 and both the client and the batch job use LOCAL_QUORUM. My question is "Will the client still read the correct data when the repair