The compression and decompression step of persist_to_workspace takes an very long time, e.g. when using docker save to save a couple of images to the workspace.Adding ZST compression can dramatically speed up this step for very similar compression ratios.See and zstd vs tar locally for the result of images saved via docker save of file size 2.4GB.time zstd test.tar -o test.tar.zstzstd test.tar -o test.tar.zst 10.85s user 0.95s system 59% cpu 19.790 totaltime tar cvzf test.tar.gz test.tartar cvzf test.tar.gz test.tar 98.86s user 4.98s system 102% cpu 1:41.71 totalFile sizes:790M ./test.tar.gz730M ./test.tar.zstAnd using more optimal settings for ZST on a quad core machine:time zstd --long -T4 -f test.tar -o test.tar.zsttest.tar : 25.75% (2483335168 => 639374809 bytes, test.tar.zst) zstd --long -T4 -f test.tar -o test.tar.zst 20.75s user 0.87s system 189% cpu 11.390 total610M ./test.tar.zstThe performance gains are substantial an would place CircleCi workflow performance at a great advantage.Decompression speed:time zstd -d test.tar.zst -o test.zst-decomp zstd -d test.tar.zst -o test.zst-decomp 2.20s user 1.42s system 91% cpu 3.962 totaltime tar -xvzf test.tar.gz tar -xvzf test.tar.gz 15.81s user 5.45s system 104% cpu 20.313 totalSome versions of tar support zst compression: