# 2021-07-25-23:07:58+0800 modify cloudchat tikv backup.num-threads to 8

- Cause: https://jira.tidbcloud.com/projects/TCOC/issues/TCOC-131?filter=allopenissues
- Operation:
    > shoot="4bc76ea", tenant="1311265642040528896, name="CC_A1"

    1. delete backup start at 2021-07-26 02:00:00

    ```bash
    k delete backup ab-1311285575352848384-{auto_increase_id}
    ```
    2. modity store limit to 15
    ```
    kubectl exec -it -n tidb1311285575352848384 db-pd-0 -- sh
    cd /var/lib/pd-tls
    # show current store limit，should be 20
    pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit store limit
    # modify store limit to 15
    pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit all 15
    # show store limit，should be 15
    pd-ctl --pd https://db-pd:2379 --cacert ca.crt --key tls.key --cert tls.crt store limit store limit
    ```

    3. modify tikv num-threads configuration

    ```bash
    # backup tidbcluster config
    k get tc db -o yaml > backup.yaml
    export KUBE_EDITOR="vim"
    k edit tc db
    # add configuration to spec.tikv
    + [backup]
    + num-threads = 8
    ```

- Impact: 
    ```
    1. backuo will failed in user's dashboard 
    2. tikv will rolling-update
    ```
- Recovery operation: `k apply -f backup.yaml`
- Time window: `2021-07-26 02:00:00 ~ 2021-07-26 02:05:00`