CR [GSTG] Increase max_wal_size from 16GB to 32GB
Production Change
Change Summary
This solves Increase max_wal_size to reduce WAL rate by increasing max_wal_size
from 16GB
to 32GB
.
Change Details
- Services Impacted - ServicePatroni, ServicePatroniCI
- Change Technician - @alexander-sosna
- Change Reviewer - @anganga
- Time tracking - <60 minutes
- Downtime Component - No downtime
Set Maintenance Mode in GitLab
If your change involves scheduled maintenance, add a step to set and unset maintenance mode per our runbooks. This will make sure SLA calculations adjust for the maintenance period.
Detailed steps for the change
Change Steps - steps to take to execute the change
Estimated Time to Complete (mins) - Estimated Time to Complete in Minutes
-
Set label changein-progress /label ~change::in-progress
-
Merge MR [GSTG] Increase max_wal_size from 16GB to 32GB to change max_wal_size
to32GB
. -
Log into CI patroni-ci-v14-101-db-gstg.c.gitlab-staging-1.internal
, check which nodes areReplica
and which is theLeader
,gitlab-patronictl list
. -
Log into each Replica
sequentially, starting with thenoloadbalance
ones.-
Run Chef chef-client
. -
Reload the configuration and check that the new value is active. gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;' postgres=# SHOW max_wal_size; max_wal_size -------------- 16GB (1 row) postgres=# SELECT pg_reload_conf(); pg_reload_conf ---------------- t (1 row) postgres=# SHOW max_wal_size; max_wal_size -------------- 32GB (1 row)
-
Check metrics, make sure standby performance did not decrease.
-
-
Check metrics, make sure none of the systems show performance degradation. -
Run Chef chef-client
on theLeader
. -
Reload configuration on the Leader
.gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;'
-
Check metrics, make sure the cluster does not show performance degradation. -
Log into MAIN patroni-main-v14-101-db-gstg.c.gitlab-staging-1.internal
, check which nodes areReplica
and which is theLeader
,gitlab-patronictl list
. -
Log into each Replica
sequentially, starting with thenoloadbalance
ones.-
Run Chef chef-client
. -
Reload the configuration and check that the new value is active. gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;' postgres=# SHOW max_wal_size; max_wal_size -------------- 16GB (1 row) postgres=# SELECT pg_reload_conf(); pg_reload_conf ---------------- t (1 row) postgres=# SHOW max_wal_size; max_wal_size -------------- 32GB (1 row)
-
Check metrics, make sure standby performance did not decrease.
-
-
Check metrics, make sure none of the systems show performance degradation. -
Run Chef chef-client
on theLeader
. -
Reload configuration on the Leader
.gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;'
-
Check metrics, make sure the cluster does not show performance degradation. -
Set label changecomplete /label ~change::complete
.
Rollback
Rollback steps - steps to be taken in the event of a need to rollback this change
Estimated Time to Complete (mins) - Estimated Time to Complete in Minutes
-
Revert MR [GSTG] Increase max_wal_size from 16GB to 32GB to change max_wal_size
to32GB
. -
Log into each standby sequentially, starting with the noloadbalance
ones.-
Run Chef chef-client
. -
Reload the configuration and check that the new value is active. gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;'
-
-
Check metrics, make sure none of the systems show performance degradation. -
Run Chef chef-client
on primary. -
Reload configuration on primary. gitlab-psql -c 'SHOW max_wal_size;' gitlab-psql -c 'SELECT pg_reload_conf();' gitlab-psql -c 'SHOW max_wal_size;'
-
Set label changeaborted /label ~change::aborted
Monitoring
Key metrics to observe
-
Metric: CI transactions_replica SLI Error Ratio
- Location: https://dashboards.gitlab.net/d/patroni-ci-main/patroni-ci3a-overview?orgId=1&var-PROMETHEUS_DS=PA258B30F88C30650&var-environment=gstg&viewPanel=438786388&from=now-30m&to=now
- What changes to this metric should prompt a rollback: increase of postgresql error ratio on nodes after resize of their filesystem should prompt removing and rebuilding the affected Replica
-
Metric: CI transactions_primary SLI Error Ratio
- Location: https://dashboards.gitlab.net/d/patroni-ci-main/patroni-ci3a-overview?orgId=1&var-PROMETHEUS_DS=PA258B30F88C30650&var-environment=gstg&viewPanel=2278903563&from=now-30m&to=now
- What changes to this metric should prompt a rollback: increase of postgresql error ratio on nodes after resize of their filesystem should prompt a switchover of the Primary into a healthy Replica, and then removing and rebuilding the affected node
-
Metric: MAIN transactions_replica SLI Error Ratio
- Location: https://dashboards.gitlab.net/d/patroni-main/patroni-ci3a-overview?orgId=1&var-PROMETHEUS_DS=PA258B30F88C30650&var-environment=gstg&viewPanel=438786388&from=now-30m&to=now
- What changes to this metric should prompt a rollback: increase of postgresql error ratio on nodes after resize of their filesystem should prompt removing and rebuilding the affected Replica
-
Metric: MAIN transactions_primary SLI Error Ratio
- Location: https://dashboards.gitlab.net/d/patroni-main/patroni-ci3a-overview?orgId=1&var-PROMETHEUS_DS=PA258B30F88C30650&var-environment=gstg&viewPanel=2278903563&from=now-30m&to=now
- What changes to this metric should prompt a rollback: increase of postgresql error ratio on nodes after resize of their filesystem should prompt a switchover of the Primary into a healthy Replica, and then removing and rebuilding the affected node
Change Reviewer checklist
-
Check if the following applies: - The scheduled day and time of execution of the change is appropriate.
- The change plan is technically accurate.
- The change plan includes estimated timing values based on previous testing.
- The change plan includes a viable rollback plan.
- The specified metrics/monitoring dashboards provide sufficient visibility for the change.
-
Check if the following applies: - The complexity of the plan is appropriate for the corresponding risk of the change. (i.e. the plan contains clear details).
- The change plan includes success measures for all steps/milestones during the execution.
- The change adequately minimizes risk within the environment/service.
- The performance implications of executing the change are well-understood and documented.
- The specified metrics/monitoring dashboards provide sufficient visibility for the change.
- If not, is it possible (or necessary) to make changes to observability platforms for added visibility?
- The change has a primary and secondary SRE with knowledge of the details available during the change window.
- The change window has been agreed with Release Managers in advance of the change. If the change is planned for APAC hours, this issue has an agreed pre-change approval.
- The labels blocks deployments and/or blocks feature-flags are applied as necessary.
Change Technician checklist
-
Check if all items below are complete: - The change plan is technically accurate.
- This Change Issue is linked to the appropriate Issue and/or Epic
- Change has been tested in staging and results noted in a comment on this issue.
- A dry-run has been conducted and results noted in a comment on this issue.
- The change execution window respects the Production Change Lock periods.
- For C1 and C2 change issues, the change event is added to the GitLab Production calendar.
- For C1 and C2 change issues, the SRE on-call has been informed prior to change being rolled out. (In #production channel, mention
@sre-oncall
and this issue and await their acknowledgement.) - For C1 and C2 change issues, the SRE on-call provided approval with the eoc_approved label on the issue.
- For C1 and C2 change issues, the Infrastructure Manager provided approval with the manager_approved label on the issue.
- Release managers have been informed prior to any C1, C2, or blocks deployments change being rolled out. (In #production channel, mention
@release-managers
and this issue and await their acknowledgment.) - There are currently no active incidents that are severity1 or severity2
- If the change involves doing maintenance on a database host, an appropriate silence targeting the host(s) should be added for the duration of the change.
Edited by Rafael Henchen