Monday, December 17, 2018

New small servers for performance testing

My old NUC cluster found a new home and I downsized to 2 new NUC servers. The new server is NUC8i7beh with 16g RAM, 500g Samsung 860 EVO for the OS and 500g Samsung 970 EVO for performance. The Samsung 860 is SATA and the Samsung 970 is an m.2 device. I expect to wear out the performance devices as I have done that in the past. With the OS on a separate device I avoid the need to reinstall the OS when that happens.

The new NUC has a post-Skylake CPU (i7-8559u), provides 4 cores (8 HW threads) compared to 2 cores (4 HW threads) in the old NUCs. I disabled turbo boost again to avoid performance variance as mentioned in the old post. I am not sure these have sufficient cooling for sustained boost and when boost isn't sustained there are frequent changed in CPU performance. I also disabled hyperthreads out of concern for both the impact from Spectre fixes and to avoid a different syscall overhead each time I update the kernel.

I might use these servers to examine the impact of the ~10x increase in PAUSE times on InnoDB with and without HT enabled. I might also use them for another round of MySQL performance testing when 8.0.14 is release.

I am a big fan of Intel NUC servers. But maybe I am not a fan of the SATA cables they use. I already had one of my old NUCs replaced under warranty after one of the SATA wires was bare. In the new NUCs I just setup a few of the SATA cables appear to be cut and I wonder if that eventually becomes bare.

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