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What does ONTAP do with available IDLE cycles on the storage controller?
https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/What_does_ONTAP_do_with_available_IDLE_cycles_on_the_storage_controller
ONTAP is opportunistic, when there are available IDLE CPU cycles (IDLE time), instead of wasting the IDLE time, ONTAP can and will use as much of the available time as possible to run background and s...ONTAP is opportunistic, when there are available IDLE CPU cycles (IDLE time), instead of wasting the IDLE time, ONTAP can and will use as much of the available time as possible to run background and scheduled tasks such as: This increased latency is expected since the storage system becomes busy with work it is doing in the background (by design), when the work is complete, utilization and latency can drop back to the normal levels.
VMware reports lost access to multiple volumes and performance impact
https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/VMware_reports_lost_access_to_multiple_volumes_and_performance_impact
Applies to VMware VMware alarms report lost access to multiple volumes for a few seconds Lost access to volume xyz due to connectivity issues. Recovery attempt is in progress and outcome will be repor...Applies to VMware VMware alarms report lost access to multiple volumes for a few seconds Lost access to volume xyz due to connectivity issues. Recovery attempt is in progress and outcome will be reported shortly. Performance impact reported by end users ONTAP System Manager reports higher latency than expected for same IOPS at protocol layer ONTAP events report error, indicating one adapter/Fabric impacted fcp.io.status Adapter:4c IO WQE failure Ext_Status 0x16
What is the Directory Indexing Scanner and what does directory indexing accomplish?
https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/What_is_the_Directory_Indexing_Scanner_and_what_does_directory_indexing_accomplish
ONTAP has scaled to meet these needs as it has evolved, and one of those features is directory indexing. Directory lookup will only read required blocks in the directory instead of entire directory. I...ONTAP has scaled to meet these needs as it has evolved, and one of those features is directory indexing. Directory lookup will only read required blocks in the directory instead of entire directory. Indexing the same 100 directories of 10 MB each in 9.2+ reduces this to around 200 MB of RAM. You will notice in "wafl scan status" a "directory index creation" scan. A frontend call (lookup/create generally) will cause ONTAP to notice that the directory is greater than 2 MB and index it.
Performance issue with SCSI errors against datastore - SCSI Sense Code : H:0x0 D:0x28 P:0x0
https://kb.netapp.com/on-prem/solidfire/Element_OS_Kbs/Performance_issue_with_SCSI_errors_against_datastore_SCSI_Sense_Code___H_0x0_D_0x28_P_0x0
Applies to Element Software 9.2.0.43 Esxi 4.x & above Issue Performance issue and SCSI errors against datastores with SCSI Sense Code : H:0x0 D:0x28 P:0x0
AIQUM 9.7+ or NSLM may enable workload AQoS causing unexpected latency
https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Active_IQ_Unified_Manager_9.7__can_enabled_aQoS_on_workloads_automatially
Cluster::> qos statistics volume latency show Workload ID Latency Network Cluster Data Disk QoS Max QoS Min NVRAM --------------- ------ ---------- ---------- ---------- ---------- ---------- --------...Cluster::> qos statistics volume latency show Workload ID Latency Network Cluster Data Disk QoS Max QoS Min NVRAM --------------- ------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ... vol1-wid21368 21368 879.73ms 283.00us 9.00us 498.00us 184.00us 0ms 877.99ms 216.00us vol2-wid19287 19287 736.25ms 401.00us 8.00us 734.00us 166.00us 0ms 734.91ms 199.00us
Snapmirror transfer speed is extremely slow
https://kb.netapp.com/on-prem/ontap/DP/SnapMirror/SnapMirror-KBs/Snapmirror_transfer_speed_is_extremely_slow
Applies to SnapMirror Issue Those destination clusters that were moved to the new IDC or initially created from new IDC all experienced the SnapMirror performance degradation issue The ONTAP resource ...Applies to SnapMirror Issue Those destination clusters that were moved to the new IDC or initially created from new IDC all experienced the SnapMirror performance degradation issue The ONTAP resource usage and the network throughput are very low The status of the cluster peer is healthy
High latency on database log volumes
https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/High_latency_on_database_log_volumes
Applies to ONTAP Issue High latency in a database environment reported against the controller NetApp Unified Manager Insight etc. This article only applies to situations where the controller is report...Applies to ONTAP Issue High latency in a database environment reported against the controller NetApp Unified Manager Insight etc. This article only applies to situations where the controller is reporting high latency for database logging volumes/LUNs
ESX Hosts losing access to LUNs regularly along with Aggregate reporting long CP's
https://kb.netapp.com/on-prem/ontap/OHW/OHW-KBs/ESX_Hosts_losing_access_to_LUNs_regularly_along_with_Aggregate_reporting_long_CP_s
Applies to VMware critical alert for datastore path down Poor performance and alerts for SQL virtual machines Affected datastores: Path redundancy to storage device naa.xyz degraded. Path vmhba1:C0:T7...Applies to VMware critical alert for datastore path down Poor performance and alerts for SQL virtual machines Affected datastores: Path redundancy to storage device naa.xyz degraded. Path vmhba1:C0:T78:L10 is down. ONTAP reports long or back2back consistency points (CP) wafl_exempt00: wafl.cp.toolong:error]: Aggregate_xyz_sata_aggr1 experienced a long CP. I/O latency increased from average value of 8000 microseconds to 1000008 microseconds
General guidance for collecting data for performance analysis ONTAP 7Mode and Cdot
https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/General_guidance_for_collecting_data_for_performance_analysis_ONTAP_7Mode_and_Cdot
For example, if the issue is reported for slow backup process or execution of some scrips takes longer then usually, data must be collected during whole process of backup and also during “normal” time...For example, if the issue is reported for slow backup process or execution of some scrips takes longer then usually, data must be collected during whole process of backup and also during “normal” time of backup (period in which backup was not taking “much longer”). Decision about timeframe for single iteration (-t parameter), number of iterations ( -i ) and number of runs may vary based on issue and is provided by TSE working on the issue via action plan.
What is new in ONTAP 9.8 Shared Memory Implementation for FPolicy?
https://kb.netapp.com/on-prem/ontap/da/NAS/NAS-KBs/What_is_new_in_ONTAP_9.8_Shared_Memory_Implementation_for_FPolicy
Netapp dramatically improved Fpolicy performance in 9.8 and above releases by implementing a new Shared Memory Implementation for Fpolicy This change improved internal ONTAP Fpolicy performance by all...Netapp dramatically improved Fpolicy performance in 9.8 and above releases by implementing a new Shared Memory Implementation for Fpolicy This change improved internal ONTAP Fpolicy performance by allowing ONTAP to be able to process more inbound IOPS processing when Fpolicy is enabled When Fpolicy is enabled, this new implementation helps to avoid performance degradation for NFS and CIFS workloads both on throughput and latency
Volumes getting high latency due to incomplete decommission of StorageGRID node
https://kb.netapp.com/hybrid/StorageGRID/Maintenance/Volumes_getting_high_latency_due_to_incomplete_decommission_of_StorageGRID_node
Decommission of VM-based node Host volumes having high latency due to incomplete decommission of storageGRID Node. We could see Decommission completed on Grid Topology > Site > Primary Admin node > CM...Decommission of VM-based node Host volumes having high latency due to incomplete decommission of storageGRID Node. We could see Decommission completed on Grid Topology > Site > Primary Admin node > CMN > Tasks but From Maintenance > Decommission page doesnt reset. Decommissionned Node logs shows it got failed, and although it should re-try the decommission on this node but instead got success message (Child process exited with RC=0) due to a known issue.