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    • How concurrency can impact throughput performance with Data ONTAP 7-Mode
      https://kb.netapp.com/Legacy/ONTAP/7Mode/How_concurrency_can_impact_throughput_performance_with_Data_ONTAP_7-Mode
      Applies to DATA ONTAP 7-Mode When reads or writes are slow for the host, Little's Law: N (concurrency) = λ (ops) * W (wait time in seconds) can be applied to determine concurrency of a volume. This is...Applies to DATA ONTAP 7-Mode When reads or writes are slow for the host, Little's Law: N (concurrency) = λ (ops) * W (wait time in seconds) can be applied to determine concurrency of a volume. This is useful because it is a quick way to measure if ONTAP is getting enough workload or a delay exists at network or host using math. Note: W is short for wait time, but ONTAP uses average response time which is a slightly different measurement than client wait time. The concept is the same in practice.
    • NAS access slow or hung caused by CRC errors on network port
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/NAS_access_slow_or_hung_caused_by_CRC_errors_on_network_port
      RECEIVE Total frames: 5161m | Frames/second: 24558 | Total bytes: 5152g Bytes/second: 24516k | Total errors: 35927 | Errors/minute: 10 Total discards: 0 | Discards/minute: 0 | Multi/broadcast: 26826k ...RECEIVE Total frames: 5161m | Frames/second: 24558 | Total bytes: 5152g Bytes/second: 24516k | Total errors: 35927 | Errors/minute: 10 Total discards: 0 | Discards/minute: 0 | Multi/broadcast: 26826k Non-primary u/c: 0 | CRC errors: 35927 | Runt frames: 0 Fragment: 0 | Long frames: 0 | Jabber: 0 Length errors: 0 | No buffer: 0 | Xon: 0 Xoff: 0 | Pause: 0 | Jumbo: 218k Noproto: 0 | Error symbol: 0 | Illegal symbol: 0 Bus overruns: 0 | Queue drops: 0 | LRO segments: 2060m LRO bytes: 4909g | LRO6 …
    • High READDIR latency on NFS or CIFS workload
      https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/High_READDIR_latency_on_NFS_or_CIFS_workload
      Applies to Data ONTAP 9 FlexGroup with NFS or CIFS workload FlexVol with NFS or CIFS workload Issue Elevated latency on NFS or CIFS FlexGroup or FlexVol, specifically on metadata (READDIR) operations.
    • _ocs_vserver workload can cause high Node utilization/latency
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/ocs_vserver_workload_can_cause_high_Node_utilization_latency
      Applies to ONTAP 9 Issue Filer can see high Node utilization when _ocs_vserver workload is running. This workload can induce high CPU and Disk utilization causing CPU/Disk saturation. This can have a ...Applies to ONTAP 9 Issue Filer can see high Node utilization when _ocs_vserver workload is running. This workload can induce high CPU and Disk utilization causing CPU/Disk saturation. This can have a negative impact on other user workload as they would starve for resources. Alarm IO wait time is reported from the vCenter.
    • Cluster Interconnect delay due to data LIFs not local to node owning disks
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Cluster_Interconnect_delay_due_to_data_LIFs_not_local_to_node_owning_disks
      cluster1::> qos statistics volume latency show -iterations 100 Workload ID Latency Network Cluster Data Disk QoS NVRAM Cloud --------------- ------ -------- -------- -------- -------- -------- -------...cluster1::> qos statistics volume latency show -iterations 100 Workload ID Latency Network Cluster Data Disk QoS NVRAM Cloud --------------- ------ -------- -------- -------- -------- -------- -------- ---------- ---------- -total- 110.35ms 0ms 110.02ms 327.00us 0ms 0ms 0ms 0ms vs1vol0 111 167.82ms 0ms 167.22ms 603.00us 0ms 0ms 0ms 0ms vol1 1234 117.76ms 0ms 117.56ms 191.00us 0ms 0ms 0ms 0ms
    • Increased latency when Oracle DB is configured with logbias=latency
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Increased_latency_when_Oracle_DB_is_configured_with_logbias_latency
      Applies to ONTAP 9 Issue Increased latency when Oracle DB is configured with logbias=latency
    • CIFS access slow due to lnk files in a root or subdirectory of a volume
      https://kb.netapp.com/on-prem/ontap/da/NAS/NAS-KBs/CIFS_access_slow_due_to_lnk_files_in_a_root_or_subdirectory_of_a_volume
      Create Request File: Windows (C) - Shortcut (3).lnk Create Response File: Windows (C) - Shortcut (3).lnk GetInfo Request SEC_INFO/SMB2_SEC_INFO_00 File: Windows (C) - Shortcut (3).lnk Read Request Len...Create Request File: Windows (C) - Shortcut (3).lnk Create Response File: Windows (C) - Shortcut (3).lnk GetInfo Request SEC_INFO/SMB2_SEC_INFO_00 File: Windows (C) - Shortcut (3).lnk Read Request Len:518 Off:0 File: Windows (C) - Shortcut (3).lnk Create Request File: Windows (C) - Shortcut (4).lnk Create Response File: Windows (C) - Shortcut (4).lnk GetInfo Request SEC_INFO/SMB2_SEC_INFO_00 File: Windows (C) - Shortcut (4).lnk Read Request Len:518 Off:0 File: Windows (C) - Shortcut (4).lnk
    • Disk bottleneck may impact VMware LUN performance and timeouts
      https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Disk_bottleneck_may_impact_VMware_LUN_performance_and_timeouts
      Applies to ONTAP 9 VMware ESXi NFS, iSCSI, or FCP Datastores Issue Significant performance issues for NFS volumes, or FCP or iSCSI LUNs on a VMWare ESXi cluster or also iSCSI LUN timeouts VMs are slow...Applies to ONTAP 9 VMware ESXi NFS, iSCSI, or FCP Datastores Issue Significant performance issues for NFS volumes, or FCP or iSCSI LUNs on a VMWare ESXi cluster or also iSCSI LUN timeouts VMs are slow on reads or writes qos statistics shows high disk latency Example: vol1 has high disk latency Workload ID Latency Network Cluster Data Disk QoS Max QoS Min NVRAM -total- - 4.33ms 198.00us 9.00us 1221.00us 2.88ms 0ms 0ms 13.00us vol1 32140 177.16ms 113.00us 226.00us 108.03ms 68.79ms 0ms 0ms 2.00us