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    • Where can I learn more about Consistency Points?
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Where_can_I_learn_more_about_Consistency_Points
      Some questions regarding Common Consistency Point, it benefits, usage, types, and measures are answered in this article.
    • What are Calculate Parity reads (CP reads) and why it makes extra disk reads?
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/What_are_Calculate_Parity_reads_CP_reads_and_why_it_makes_extra_disk_reads
      Disk cpreads are blocks that are read by RAID to satisfy a write known as Calculate Parity Reads Consistency Point are a normal state of Data ONTAP processing under which dirty buffers are de-staged t...Disk cpreads are blocks that are read by RAID to satisfy a write known as Calculate Parity Reads Consistency Point are a normal state of Data ONTAP processing under which dirty buffers are de-staged to disk From statit, cpreads column refers to CP reads (Calculate Parity Reads) these are extra reads apart from user reads which can also contribute to Disk reads
    • wafl.cp.toolong or high disk utilization on archive, backup, or disaster recovery nodes
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/wafl_cp_toolong_or_high_disk_utilization_on_archive_backup_or_disaster_recovery_nodes
      disk ut% xfers ureads--chain-usecs writes--chain-usecs cpreads-chain-usecs greads--chain-usecs gwrites-chain-usecs /data_aggr1/plex0/rg0: 0a.11.1 10 23.42 0.00 .... . 11.21 61.56 133 12.21 57.15 50 0....disk ut% xfers ureads--chain-usecs writes--chain-usecs cpreads-chain-usecs greads--chain-usecs gwrites-chain-usecs /data_aggr1/plex0/rg0: 0a.11.1 10 23.42 0.00 .... . 11.21 61.56 133 12.21 57.15 50 0.00 .... . 0.00 .... . 0a.10.1 11 23.80 0.00 .... . 11.66 59.25 147 12.14 57.37 55 0.00 .... . 0.00 .... . 1a.12.1 100 158.69 120.29 5.43 2299 10.26 34.39 553 28.15 9.93 839 0.00 .... . 0.00 .... . 0a.11.2 100 156.09 118.85 5.39 2253 9.96 34.97 553 27.28 10.05 794 0.00 .... . 0.00 .... . 0a.10.2 100…
    • Bursty write workload could affect performance
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Bursty_write_workload_could_affect_performance
      Applies to ONTAP 9.x ONTAP 8.x Back to Back CP (B2B) Issue High write workload overwhelm WAFL processing layer which lead to high write latency and performance impact due to B2B CPs. CPU is high (near...Applies to ONTAP 9.x ONTAP 8.x Back to Back CP (B2B) Issue High write workload overwhelm WAFL processing layer which lead to high write latency and performance impact due to B2B CPs. CPU is high (near or at 100%) constantly with increase in WRITE workload.
    • "wafl.cp.toolong" message seen in ONTAP Logs during high disk workload
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/wafl_cp_toolong_message_seen_in_ONTAP_Logs_during_high_disk_workload
      High disk workload when the message is detected. Event visible in the "event log show" command output: ONTAP 9 or newer Example: Mon Dec 23 00:20:36 EST [FilerA: wafl_exempt08: wafl.cp.toolong:error]:...High disk workload when the message is detected. Event visible in the "event log show" command output: ONTAP 9 or newer Example: Mon Dec 23 00:20:36 EST [FilerA: wafl_exempt08: wafl.cp.toolong:error]: Aggregate fas_01_DATA_AGGR experienced a long CP... Mon Feb 22 16:14:08 CLT [FilerA: wafl_CP_proc: wafl.cp.toolong.warning:warning]: params: ... Mon Feb 22 16:14:08 CLT [FilerA: wafl_CP_proc: wafl.cp.slovol.warning:warning]: params: ... Latency in affected aggregate is usually detected.
    • SnapMirror Synchronous multiple volumes are getting out of sync
      https://kb.netapp.com/on-prem/ontap/DP/SnapMirror/SnapMirror-KBs/SnapMirror_Synchronous_multiple_volumes_are_getting_out_of_sync
      Applies to ONTAP 9 Snapmirror Synchroniuous (SM-S) SnapMirror active sync (formerly SnapMirror Business Continuity - SMBC) Consistency point (CP) Issue The following error is reported: Failed to get S...Applies to ONTAP 9 Snapmirror Synchroniuous (SM-S) SnapMirror active sync (formerly SnapMirror Business Continuity - SMBC) Consistency point (CP) Issue The following error is reported: Failed to get Snapshot copy list for volume <vserver>:<volume>. SnapMirror Common Snapshot creation operation failed when creating Snapshot copies "<snapshot~>" on source "<UUID>:<volume>" and destination "<UUID>:<volume>".
    • What is Consistency Point, and why does NetApp use it?
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/What_is_Consistency_Point_and_why_does_NetApp_use_it
      This can be calculated as 1/2 the NVRAM size for stand-alone systems, 1/4 the NVRAM size for clustered systems, and 1/8 the NVRAM size for 4/8-node MetroClusters. As soon as the process to log to loca...This can be calculated as 1/2 the NVRAM size for stand-alone systems, 1/4 the NVRAM size for clustered systems, and 1/8 the NVRAM size for 4/8-node MetroClusters. As soon as the process to log to local NVRAM and the HA partner is confirmed, the controller acknowledges the write as completed to the client machine (app, protocol?). During the writing phase of one memory buffer, the second memory buffer and NVRAM space ( both local and remote ) are used to store and acknowledge incoming writes.
    • Write Performance Impacted by Back to Back Consistency Points
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Write_Performance_Impacted_by_Back_to_Back_Consistency_Points
      Applies to ONTAP 9 Non-AFF controllers more susceptible to this issue Issue A FlexVol or FlexGroup is experiencing increased / higher than expected write latency. Latency is reported as Data or Disk o...Applies to ONTAP 9 Non-AFF controllers more susceptible to this issue Issue A FlexVol or FlexGroup is experiencing increased / higher than expected write latency. Latency is reported as Data or Disk or WAFL Susp CP latency from qos statistics or AIQ Latency reported coincides exactly with WRITE workload increase. systat -x output shows evidence of CP type CP_Ty B (Back-to-Back) CPs
    • First steps troubleshooting Netapp FAS error wafl_exempt10: wafl.cp.toolong
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/First_steps_troubleshooting_wafl_exempt10__wafl_cp_toolong_error
      Applies to Netapp FAS Performance Issue Slow read response, or write response observed. wafl.cp.toolong:error observed in the node's event logs. Long CPs (Consistency Points) can potentially impact st...Applies to Netapp FAS Performance Issue Slow read response, or write response observed. wafl.cp.toolong:error observed in the node's event logs. Long CPs (Consistency Points) can potentially impact storage performance.