Richard Siemers wrote:
On the hosts that are latency 'victims', how many IOPs are they averaging when seeing the 20ms write latency? I ask because very low IO/idle hosts can report high latency when other systems are getting priority, however when other systems actually need to do some real IO, the latency corrects itself and the get a share of the pie too. I am not sure if this is part of the intelligent optimization, or if it's just math anomaly from calculating an "average" with too few data points.
So, if may piggyback on this. When I look at the performance charts from SSMC. I see 13 hosts showing high latency ranging from 25ms to 80ms for a period of time every night around 11PM, but 12 of them are barely doing any IOPS during that period. So, all those 12 hosts` high latency can be ignored?
That 1 host which is an SQL server is doing close to 8000 IOPs and has read latency between 30ms and 40ms which is still high for an all-flash Primera array. That lasts about an hour.
What do you suggest?