# Module cartridge.issues

Monitor issues across cluster instances.

Cartridge detects the following problems:

Replication:

- critical: “Replication from … to … isn’t running” - when `box.info.replication.upstream == nil` ;

- critical: “Replication from … to … state “stopped”/”orphan”/etc. (…)”;

- warning: “Replication from … to …: high lag” - when `upstream.lag > box.cfg.replication_sync_lag` ;

- warning: “Replication from … to …: long idle” - when `upstream.idle > 2 * box.cfg.replication_timeout` ;

Failover:

- warning: “Can’t obtain failover coordinator (…)”;

- warning: “There is no active failover coordinator”;

- warning: “Failover is stuck on …: Error fetching appointments (…)”;

- warning: “Failover is stuck on …: Failover fiber is dead” - this is likely a bug;

Switchover:

- warning: “Consistency on … isn’t reached yet”;

Clock:

- warning: “Clock difference between … and … exceed threshold” `limits.clock_delta_threshold_warning` ;

Memory:

- critical: “Running out of memory on …” - when all 3 metrics items_used_ratio, arena_used_ratio, quota_used_ratio from `box.slab.info()` exceed `limits.fragmentation_threshold_critical` ;

- warning: “Memory is highly fragmented on …” - when `items_used_ratio > limits.fragmentation_threshold_warning` and both arena_used_ratio, quota_used_ratio exceed critical limit;

Configuration:

- warning: “Configuration checksum mismatch on …”;

- warning: “Configuration is prepared and locked on …”;

- warning: “Advertise URI (…) differs from clusterwide config (…)”;

- warning: “Configuring roles is stuck on … and hangs for … so far”;

Alien members:

- warning: “Instance … with alien uuid is in the membership” - when two separate clusters share the same cluster cookie;

## Tables

### limits

Thresholds for issuing warnings. All settings are local, not clusterwide. They can be changed with corresponding environment variables ( `TARANTOOL_*` ) or command-line arguments. See cartridge.argparse module for details.

Fields:

- fragmentation_threshold_critical: (number) default: 0.9.

- fragmentation_threshold_warning: (number) default: 0.6.

- clock_delta_threshold_warning: (number) default: 5.