[tor-relays] No disk space for new files created by Tor

Dear All, Today when I was checking my Tor notice log file as usual, I noticed that they've included the following warnings: Aug 11 06:23:15.000 [warn] Unable to store router descriptorAug 11 06:23:15.000 [warn] Error writing to "/var/lib/tor/cached-descriptors.new": No space left on device It seems that I've run out of space. But my VPS comes with 35GB disk space and it shouldn't be used up so fast. So how to deal with it?If I do run out of space,any advice for deleting the old files of Tor? Are there any files created by Tor are not useful anymore and can be deleted?

Cheers,Tony