Hi,all
VDSM have realized the feature of thin provision in its released version.
Volumes have 2 major properties: 1. type - How are the bits written to the underlying volume. o raw - means a simple raw access a write to offset X will be written on offset X o qcow2 - means that the storage will be accessed as a qcow2 image and all that this entails 2. allocation - How should VDSM allocated the storage o preallocated - VDSM will try it's best to guaranty that all the storage that was requested is allocated right away. Some storage configuration may render preallocation pointless. o sparse/thin provision - space will be allocated for the volume as needed
As is known to all, thin provision means allocating the disk space once the instance writes the data on the area of volume in the first time. The size of the disk will be increasing even though we have deleted the file in the instance.
With the latest feature of qemu, the disk can be shrinked. Ref link: http://dustymabe.com/2013/06/11/recover-space-from-vm-disk-images-by-using-d...
Does VDSM have any plan for this?
Thanks,
Qi ________________________________ Xiaozhen Qi Huawei Technologies Co.,LTD. IT Product Line CloudOS PDU China, Xi'an Mobile: +86-13609283376 Email: qixiaozhen@huawei.com
On 01/13/2014 04:19 AM, Qixiaozhen wrote:
Hi,all
VDSM have realized the feature of thin provision in its released version.
Volumes have 2 major properties:
1.*type*- How are the bits written to the underlying volume.
o/raw/- means a simple raw access a write to offset X will be written on offset X
o/qcow2/- means that the storage will be accessed as a qcow2 image and all that this entails
2.*allocation*- How should VDSM allocated the storage
o/preallocated/- VDSM will try it's best to guaranty that all the storage that was requested is allocated right away. Some storage configuration may render preallocation pointless.
o/sparse/thin provision/- space will be allocated for the volume as needed
As is known to all, thin provision means allocating the disk space once the instance writes the data on the area of volume in the first time. The size of the disk will be increasing even though we have deleted the file in the instance.
With the latest feature of qemu, the disk can be shrinked. Ref link: http://dustymabe.com/2013/06/11/recover-space-from-vm-disk-images-by-using-d...
Does VDSM have any plan for this?
we have a long list of features folks are interested in. please open a bugzilla RFE if you are interested in this feature. of course, we would be more than happy if you would like to try and collaborate on implementing this.
please note while this may work for NFS, it may require extra work for iscsi which uses an LV which may have to be shrinked as well.
On 01/13/2014 04:19 AM, Qixiaozhen wrote:
Hi,all
VDSM have realized the feature of thin provision in its released version.
Volumes have 2 major properties:
1.*type*- How are the bits written to the underlying volume.
o/raw/- means a simple raw access a write to offset X will be written on offset X
o/qcow2/- means that the storage will be accessed as a qcow2 image and all that this entails
2.*allocation*- How should VDSM allocated the storage
o/preallocated/- VDSM will try it's best to guaranty that all the storage that was requested is allocated right away. Some storage configuration may render preallocation pointless.
o/sparse/thin provision/- space will be allocated for the volume as needed
As is known to all, thin provision means allocating the disk space once the instance writes the data on the area of volume in the first time. The size of the disk will be increasing even though we have deleted the file in the instance.
With the latest feature of qemu, the disk can be shrinked. Ref link: http://dustymabe.com/2013/06/11/recover-space-from-vm-disk-images-by-u sing-discardfstrim/
Does VDSM have any plan for this?
we have a long list of features folks are interested in. please open a bugzilla RFE if you are interested in this feature. of course, we would be more than happy if you would like to try and collaborate on implementing this.
please note while this may work for NFS, it may require extra work for iscsi which uses an LV which may have to be shrinked as well.
Agree with this. Shrinking raw or qcow2 images will be taken effect in the use of NFS.
However, according to the information I have, qemu 1.5 supports shrinking for raw image, and 1.6 for qcow2.
I am afraid that The version of qemu in VDSM was too low.
vdsm-devel@lists.fedorahosted.org