I am currently trying to speed up tiling using lastile with the -cores option. The data is indexed and prepared for lastile, but when I use all my available cores (48), the system just idles for roughly 90% of the time.
iostat -m fabio-debugging: Thu Oct 27 14:37:08 2022
Linux 5.4.209-116.367.amzn2.x86_64 (fabio-debugging) 10/27/22 _x86_64_ (48 CPU)
avg-cpu: %user %nice %system %iowait %steal %idle
7.49 0.00 1.68 0.09 0.00 90.73
Device tps MB_read/s MB_wrtn/s MB_dscd/s MB_read MB_wrtn MB_dscd
md0 1344.79 33.73 104.42 407.90 160189 495860 1936983
nvme0n1 7.01 0.09 0.20 0.00 445 969 0
nvme1n1 626.39 15.05 50.53 203.98 71479 239967 968628
nvme2n1 627.31 14.99 50.40 203.92 71175 239311 968354
nvme1n1 is my input disk and nvme2n1, the output one. I can't help but wonder why I have roughly the same amount of reads and writes from both input and output disks. Is there something wrong with my setup?
In any case, is there a recommended number of cores for IO using separate input and output NVMEs. Regardless of the possible problem with my setup I would be interested to hear if someone has tried that out already.
Best,
--
Fabio Picchi I Backend Developer
Tillinmäentie 3B, 02330 Espoo, Finland