Solution: 1. Initiate rebalance: ceph osd reweight -by-utilization 2. Monitor the rebalance: ceph status Explanation: Rebalancing ensures optimal distribution of data across OSDs for better performance. Monitor MON storage usage and clean up old data if needed. ee the solution below. Solution: 1. Check MON disk usage: df -h /var/lib/ceph/mon 2. Remove old logs or snapshots if required. Explanation: Regular monitoring prevents MON storage from becoming a bottleneck for cluster operations. Enable detailed OSD logging for troubleshooting. ee the solution below. Solution: 1. Increase the debug level: ceph config set osd debug_osd 10/10 2. View the logs: journalctl -u ceph -osd@<osd -id>
Explanation: Detailed OSD logs provide valuable insights for identifying and resolving issues. Manually resolve PGs stuck in "inconsistent" state. ee the solution below. Solution: 1. Identify inconsistent PGs: ceph pg dump_stuck inconsistent 2. Repair the PG: ceph pg repair <pg -id> 3. Verify the PG state: ceph health detail Explanation: Repairing inconsistent PGs ensures data integrity and resolves cluster health warnings. Mark a MON for decommissioning and remove it from the cluster. ee the solution below. Solution: 1. Mark the MON as out: ceph mon out <mon -id> 2. Remove the MON from the cluster: ceph mon remove <mon -id> 3. Verify the updated monitor quorum: ceph quorum_status
Explanation: Removing unused or failed monitors ensures the cluster quorum remains stable and healthy. Reduce the replication size for a pool to free up storage. ee the solution below. Solution: 1. View the current replication size: ceph osd pool get <pool -name> size 2. Set a lower replication size: ceph osd pool set <pool -name> size 2 3. Verify the new configuration: ceph osd pool get <pool -name> size Explanation: Lowering replication size frees up storage but reduces redundancy, so it should be done with caution. Restore a MON quorum after multiple MON failures. ee the solution below. Solution: 1. Identify the remaining MONs: ceph mon stat 2. Reinitialize the quorum: ceph -mon -i <mon -id> --force -quorum 3. Verify the restored quorum: ceph quorum_status
Explanation: Restoring quorum ensures the cluster regains its ability to make decisions and operate normally. Configure a maintenance mode for a MON or OSD to prevent data movement. ee the solution below. Solution: 1. Set the "noout" flag for the MON or OSD: ceph osd set noout 2. Perform maintenance tasks. 3. Unset the "noout" flag after maintenance: ceph osd unset noout Explanation: Maintenance mode prevents unnecessary backfilling or recovery processes during short -term node maintenance. Set key network tuning parameters to optimize the Ceph cluster's performance. ee the solution below. Solution: 1. Increase the TCP buffer sizes: sysctl -w net.core.rmem_max=268435456 sysctl -w net.core.wmem_max=268435456 2. Persist changes in /etc/sysctl.conf: echo "net.core.rmem_max=268435456" >> /etc/sysctl.conf echo "net.core.wmem_max=268435456" >> /etc/sysctl.conf 3. Apply changes:
sysctl -p Explanation: Tuning TCP buffer sizes improves network throughput, particularly for high-latency networks in distributed storage clusters. Enable jumbo frames to improve network performance in a Ceph cluster. ee the solution below. Solution: 1. Set the MTU to 9000 for the network interface: ip link set dev <interface -name> mtu 9000 2. Make the changes persistent by editing /etc/sysconfig/network -scripts/ifcfg -<interface -name>: MTU=9000 3. Restart the network service: systemctl restart network Explanation: Jumbo frames reduce overhead by transmitting larger packets, enhancing the efficiency of large data transfers. Control and manage scrubbing frequency to minimize performance impact. ee the solution below. Solution: 1. Set the interval for scrubbing: ceph config set osd osd_scrub_begin_hour 2 ceph config set osd osd_scrub_end_hour 6 2. Verify the configuration:
ceph config dump | grep osd_scrub Explanation: Restricting scrubbing to off -peak hours minimizes its impact on cluster performance during busy periods. Control deep scrubbing frequency in a Ceph cluster. ee the solution below. Solution: 1. Adjust the interval for deep scrubbing: ceph config set osd osd_deep_scrub_interval 604800 2. Verify the configuration: ceph config dump | grep osd_deep_scrub_interval Explanation: Deep scrubbing checks the integrity of data at the block level. Adjusting its frequency balances performance and data integrity. Limit the number of simultaneous scrubbing operations. ee the solution below. Solution: 1. Set the maximum scrubs per OSD: ceph config set osd osd_max_scrubs 2 2. Verify the setting: ceph config dump | grep osd_max_scrubs Explanation: Limiting simultaneous scrubs reduces resource contention, ensuring smooth cluster operations.
