On 10/05/16 21:47, Denis V. Lunev wrote: > On 10/05/2016 09:55 PM, Laszlo Ersek wrote: >> On 10/03/16 16:01, Denis V. Lunev wrote: >>> Unfortunately, there is no public Windows API to start trimming the >>> filesystem. The only viable way here is to call 'defrag.exe /L' for >>> each volume. >>> >>> This is working since Win8 and Win2k12. >>> >>> Signed-off-by: Denis V. Lunev <d...@openvz.org> >>> Signed-off-by: Denis Plotnikov <dplotni...@virtuozzo.com> >>> CC: Michael Roth <mdr...@linux.vnet.ibm.com> >>> CC: Stefan Weil <s...@weilnetz.de> >>> CC: Marc-André Lureau <marcandre.lur...@gmail.com> >>> --- >>> qga/commands-win32.c | 97 >>> ++++++++++++++++++++++++++++++++++++++++++++++++++-- >>> 1 file changed, 94 insertions(+), 3 deletions(-) >> Just to educate myself (really, you can ignore my question as "review >> comment", because it's not one): why is this necessary? In Windows 8 and >> Windows Server 2012 R2, simply putting your NTFS filesystem on a SCSI >> disk (such as virtio-scsi-pci / scsi-hd) or AHCI, and specifying >> discard=on for the -drive, will result in the guest automatically >> trimming the NTFS (with a little delay) after deleting files, and the >> host getting those blocks back. > The same as for Linux. But if the one exact block has been freed > by half at one operation and by another half in the different operation > as far as I could understand it will not be freed. > > This patch implements the ability to trim all the disc as done for Linux > to go over all the disc and discard all possible areas. I think that this > would be useful f.e. to prepare template images.
Thank you for explaining. And, now I've learned about "defrag /L" too :) Cheers Laszlo
