I have VirtualBox 4.1.14 on Windows 7 as host, and Ubuntu server 11.10 as guest. System was installed at traditional HDD years ago (and upgraded later), but now it's at SSD as expanding drive. There is "AHCI" and "it's SSD" features enabled in SATA controller. Problem is, this expanding drive growth to it's almost max size (90% of it), but actually in VM only about 50% spent. Also, guest VM does not recognize /dev/sda as SSD, /sys/block/sda/queue/rotational says "1", /sys/block/sda/queue/discard_* all says "0". And, of course, I cannot run fstrim /, it says that operation not supported. Is there some trick to enable TRIM support in my guest system without reinstalling it?