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 Post subject: Re: High storage latency 3Par 8200 and Vmware
PostPosted: Wed Sep 12, 2018 9:12 am 

Joined: Tue Sep 04, 2018 4:53 am
Posts: 6
Thanks for the analysis jgmke, They are definitely SSD drives:-

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ssd.PNG
ssd.PNG [ 145.56 KiB | Viewed 98 times ]


I do have some positive progress to report, I changed the interconnects for Synergy to Switch to the 'correct' QSFP's and fibers this morning. It has made a big difference to latency. I also have IOmeter up and running now and you can clearly see on the graph below once the IOP's are ramped up the latency goes down to the sort of figures we were hoping/expecting to see.

Attachment:
iops.PNG
iops.PNG [ 125.95 KiB | Viewed 98 times ]


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 Post subject: Re: High storage latency 3Par 8200 and Vmware
PostPosted: Mon Sep 17, 2018 7:30 pm 

Joined: Sun Apr 23, 2017 5:45 pm
Posts: 17
Service times always show as high when there is not much IO happening on our system. We run iSCSI also.

Your numbers look much better in your latest screen grab.


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 Post subject: Re: High storage latency 3Par 8200 and Vmware
PostPosted: Fri Sep 21, 2018 3:23 am 

Joined: Tue Sep 04, 2018 4:53 am
Posts: 6
Another follow up. As part of dealing with another unrelated VMware issue we were recommended by HPE to temporarily switch to using VMware native s/w iSCSI while further analysis is carried out. Post change i have seen a dramatic drop in latency. Why would s/w iSCSI perform so much better than hardware? :shock:

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