Looks like I have found a KB article KB66042 which addresses this issue. These logs were generated by the application server, when it used to be ePO 4.0 in 2011. Since going to ePO 4.6 these are not used or generated. the KB article says that you can safely delete these logs, which have saved 1.9GB in space.
Yes, you can esily remove these logs, in epo4.6 these logs are disabled by default.So you need not to follow that KB, it is only for ePO 4.0