Re: [Qemu-devel] trim in windows guest witch virtio

[Libaiqing]

Hi paolo,

    I test window guest with ide device with the following config,trim with ide 
drive failed.

     1 The host fs is ext4 with discard option: 
       /dev/sdb1 on /home/sdb type ext4 (rw,relatime,discard,data=ordered)
     
     2 qemu config : ide drive with discard open
x86_64-softmmu/qemu-system-x86_64 -enable-kvm -name win7 -M pc-0.15 -m 1024 
-smp 2 -boot c -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2  -drive 
file=/home/win7_base.qcow2,if=ide,index=0,format=qcow2,id=ad  -drive 
file=/home/sdb/raw.img,if=ide,index=1,format=raw,id=hd,discard=on  -monitor 
stdio   -vga qxl  -vnc :1 -device usb-tablet,id=input0
     
     3 In win7 guest,init drive d,fill it with files,then shift+del files

     4 The file /home/sdb/raw.img does not become small,when listing with -s 
option.

     It seems that the windows ntfs does not send trim to ide controller. No 
IDE_DMA_TRIM request received.

     Is there any config wrong?

     Btw,I found the info from the URL: 
http://msdn.microsoft.com/en-us/library/windows/desktop/hh848053(v=vs.85).aspx
     Qemu can do the same thing like hyper-v with windows guest?

Thanks 
baiqing

> -----Original Message-----
> From: Paolo Bonzini [mailto:address@hidden
> Sent: Tuesday, July 23, 2013 2:35 PM
> To: Libaiqing
> Cc: address@hidden
> Subject: Re: trim in windows guest witch virtio
> 
> Il 23/07/2013 03:05, Libaiqing ha scritto:
> > Hi paolo,
> >     Recently I test trim function,and it works well in linux guest with ext4
> fs.
> >
> >     How to test it in windows guest? I got some info like this:
> >       1 windows7 can send discard command when the storage device is
> ssd;
> >       2 find a tool like 'fstrim', 'TRIM' the volume manually.
> 
> I think it only works with IDE and AHCI on Windows.  You need a filter
> driver to send it on SCSI disks.
> 
> Paolo