High latency is seen during SVM DR initialization
Applies to
- ONTAP 9
- SVM DR
- Performance
Issue
- SVM DR snapmirror initialization is started
- Some time later it is noted that VMs are not responding and high latency is seen on ESXi servers
- QOS statistics indicate that most of the latency is due to disk
cluster::> qos statistics volume latency show -vserver svm_lv_esx -volume LV_ESX_01
Workload ID Latency Network Cluster Data Disk QoS Max QoS Min NVRAM Cloud FlexCache SM Sync VA
--------------- ------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
-total- - 23.71ms 81.00us 44.00us 5.56ms 18.01ms 0ms 0ms 12.00us 0ms 0ms 0ms 0ms
LV_ESX_01-wid.. 57540 100.60ms 65.00us 0ms 208.00us 100.33ms 0ms 0ms 2.00us 0ms 0ms 0ms 0ms
-total- - 18.64ms 81.00us 56.00us 4.75ms 13.74ms 0ms 0ms 15.00us 0ms 0ms 0ms 0ms
LV_ESX_01-wid.. 57540 73.35ms 207.00us 0ms 114.00us 73.02ms 0ms 0ms 14.00us 0ms 0ms 0ms 0ms
- Disk statistics are reviewed to find that all disks are 100% utilized with mostly reads
cluster::> system node run -node <node>
node> statit -b
(wait a 30 seconds)
node> statit -e