If you have a data set that you delete regularly it is sometimes faster to put it on a different partition and then unmount+mkfs that partition. Depending on the number of files that will be considerably faster than rm -rf.
Regarding the performance, it might be worthwhile to use bonnie++ to test the speed of file creation and deletion. Out of curiosity I tested doing 2 million create/deletes, once on a linode VPS and another on a supermicro box with an LSI Megaraid with a 6 disk raid10 in it. Here is the VPS:
Version 1.96 ------Sequential Create------ --------Random Create--------
Linode VPS -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
1000 10650 34 152365 99 348 0 10856 35 180476 99 261 0
Latency 1468ms 9929us 13035ms 2528ms 2023us 9952ms
Supermicro+LSI:
Version 1.96 ------Sequential Create------ --------Random Create--------
LSI -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
2000 18275 23 697591 99 1201 1 18436 23 842312 99 2356 3
Latency 1847ms 515us 9160ms 1519ms 85us 7116ms
Bonnie++ command:
# bonnie++ -u nobody -d . -c 10 -s 0 -r 0 -n 2000