So far so good.. nodes stable powered on for weeks.. no load yet though. They are VMs on ESXi 6 which is directly installed on the hardware, no additional virtualization layer, however I'm facing a big problem: unfortunately in this setup I don't have a RAID or SSD underneath but just poor independent sata spindles holding datastores.. so obviously as stated before I really don't expect anything performance wise until I'll be able to move to a RAID or SSD.
However at this point please advise on the following: given the various internal (background) ONTAP / WAFL tasks that produce I/O which ones would it be safe to disable to save some ops? I've noticed the nodes taking scheduled system backups and found that these cannot be disabled. Fine, what can we safely disable?
There are not a lot of things you can adjust on that front. Most of the IO activity is from logging and the cluster DBs on the node root aggregates. You can disable ASUP, but I think the files are still generated they just aren't sent.
Even on local SSD, don't expect a lot of performance. The simulated disk subsystem is a really good simulation, but its not designed for performance. We have Data ONTAP Edge and CloudONTAP for that.
However there are a few things you can do to minimize disk IO inside the sim:
-Give the sim as much RAM as you can: 8gb or more. system RAM is the primary read cache so the more you have the better your cache hit rate will be, and the fewer reads will have to come from the simulated disks.
-Use smaller raid group sizes with larger disks, and use RAID4. Within the confines of the simulator a 3x9gb raid4 is better than a 20x1gb raid-dp because at the bottom of the funnel they all share a single VMDK anyway.
-If you use dedupe, set it for on-demand. It generates a lot of IO so you don't want it running while you are doing other testing.
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