タイル変換自宅サーバより500円VPSのほうが10倍速く終わった……

$ date;time GDAL_CACHEMAX=2048 gdal2tiles.py -z 12-19 --s_srs EPSG:2444 -a "0,0,0" ./merged.vrt ./tile;date
Mon 13 May 2019 10:43:51 PM JST
Generating Base Tiles:
0...10...20...30...40...50...60...70...80...90...100
Generating Overview Tiles:
0...10...20...30...40...50...60...70...80...90...100

real 756m23.380s
user 565m11.841s
sys 42m54.179s
Tue 14 May 2019 11:20:15 AM JST