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Azure CVO disk latency seen for subset of disks

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48
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Category:
cloud-volumes-ontap-cvo
Specialty:
perf
Last Updated:

Applies to

  • ONTAP 9
  • CVO HA
  • Azure
  • Page blob disks

Issue

  • DNS TTL values may report incorrectly.
    • Azure best practice of page blobs is 60 second TTL.
  • Disks will report 100% utilization and higher latency will be seen.
    • Could be a subset of disks or all disks on node.
cluster::> set -privilege advanced

Warning: These advanced commands are potentially dangerous; use them only when directed to do so by NetApp personnel.
Do you want to continue? {y|n}: y

cluster::*> name-service cache hosts forward-lookup show -vserver <cluster_name> <--Make sure the SVM name matches cluster name before the prompt (::*> in this case)
  (vserver services name-service cache hosts forward-lookup show)
                   IP       Address IP                     Create
Vserver   Host     Protocol Family  Address        Source  Time       TTL(sec)
--------- -------- -------- ------- -------------- ------- ---------- --------
cluster        pageblobhost.blob.core.windows.net    Any Ipv4 dns     53050
                                    20.1.2.3               11/28/
                                                           2023
                                                           09:22:43
cluster        pageblobhost.blob.core.windows.net    Any Ipv4 dns     25462
                                    20.1.2.3              11/28/
                                                           2023
                                                           09:26:40
...
cluster::*> run -node node1 statit -b
... (wait 30 seconds)
cluster::*> run -node node1 statit -e
...
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   ....     .  


cluster::> qos statistics volume latency show -vserver svm1 -volume vol1
Workload            ID    Latency    Network    Cluster       Data     Disk    QoS Max    QoS Min      NVRAM  
--------------- ------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
-total-              -     4.71ms   185.00us     7.00us   468.00us     4.04ms        0ms        0ms     11.03s
vol1-wid32140    32140     22.22s    86.00us   125.00us   904.00us   321.11ms        0ms        0ms     16.34s
 

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