Reclaiming disk space with storage vmotion and thin provisioning. Reclaiming thin provisioned storage space with vmware unmap. A virtual guest drive could be thick provisioned but the underlying storage could be thin provisioned known as thick on thin. Having thin provisioned disk is usually no longer a performance problem so it is a valid design choice even in production. I see a lot of questions and answers surrounding thin provisioning on vmware esxi but not exactly what im encountering. This discrepancy can lead to storage oversubscription, also called over provisioning. If youve cleaned up space on a thin provisioned disk and want to reclaim it then you need to use sdelete. Vmware admins also need to keep an eye on capacity alerts, because thin provisioned vms grow over time. Identify disk usage of a thin provisioned virtual disk. It requires planning for storage deployment and execution on the host and client application.
Free up esxi local drive vmfs datastore space after. I know i cannot shrink a thin provisioned drive and everything ive read says use the vm converter and it requires a downtime. Using sdelete and vmkfstools to reclaim thin vmdk space. A fresh install of ise results in around 45gb disk image for a thin provisioned disk but after installing patches and upgrading, the disk starts growing. Nothing is happening after giving the vmkfstool command. Reclaiming thin provisioned storage space with vmware. When a file is deleted from the virtual machine os, the free space is available for the os, but the disk file on the datastorestorage domain is not reduced and will keep being considered as used. One more note before it comes up by my readers, vmware tools shrinking functionality is not support on thin provisioned disks.
Shrinking a thin provisioned volume is only supported in v4 or higher. If a customer creates a 100gb disk and only uses 20gb there will be a virtual disk on the esx datastore that uses 20gb. For a thin virtual disk, esxi provisions the entire space required for the disks current and future activities, for example 40gb. To be honest this issue is more related to the guest file systems that does never delete the block data, but only the metada or some of them. When you have some vms with thin provisioned disks, you may have noticed that these will continue to grow, and never shrink, even after cleaning out data from within the vm. This is actually the same concept as for instance a vcb full image dump, which i addressed in the beginning of 2008. A virtual disk that immediately occupies the entire provisioned space is a thick disk. Reclaiming disk space with storage vmotion and thin. The storage browser displays both, the actual size and the provisioned size. On windows guests we can use the sysinternals tool sdelete replace the drive.
If you d0 not zero out your disk before you do the storage vmotion and migration to a thin provisioned disk you will be copying all the filled blocks. Best practices for defragmenting thin provisioned storage. The shrink option is unavailable if the disk is thin provisioned. Shrinking a thick provisioned disk in vmware esxi 5. What is the best way to shrink a thin provisioned disk. Open a ssh connection to the esxi host and navigate to the virtual machine folder. Storage vmotion the vm to another datastore, but the vmdk is still the same size 4. With the disklevel thin provisioning feature, you can create virtual disks in a thin format. How to reclaim disk space from virtual machines with thin virtual disks in.
Its true that the shrink option can be used for this as well as long as the disk is already thick provisioned. The entire disk space is reserved and unavailable for use by other virtual machines. Reclaiming thin disk space with storage vmotion and sdelete. Shrinking thinprovisioned esxi disks miscellaneous. For example, if you create a new thinprovisioned 30gb virtual disk and copy 10 gb of files to it, the size of the resulting vmdk file will be 10 gb, whereas you would have a 30gb vmdk file if you had chosen to use a thickprovisioned disk. In the vmware case, if you create a thinprovisioned disk, its going to grow. That is the reason behind me not using it in this post. The problem with thinprovisioned disks raxco software blog. With esxi, you can use two models of thin provisioning, arraylevel and virtual disk level. Thinprovisioned virtual disks are quick to create and useful for saving storage space. But this sounded risky to me for asm, also those utilities need an ext filesystem.
If that customer performs an operation requiring another 40gb the virtual disk on the datastore expands to 60gb. How can i reduce thin provisioned allocation of vmdk that is. Windows server thin provisioning features serve as interfaces between the thin provisioningcapable storage and the host server. The disk has not been touched yet, so the size is displayed with 0 kb.
How to shrink a thin provisioned virtual disk vmdk. From all ive read, im expecting the physical size of the vmdk file to be less than 100gb. The reason for this is that i often need to download the vm to usb storage of whatever and transfer it. They dont shrink on their own to release freed disk space. I wanted to take a moment and discuss the issue that my client ran into and why. This is required to reclaim space back from the virtual disk. Not only do they allow over provisioning, but with the prevalence of flash storage, performance degradation really isnt a concern like it used to be. Shrinking thinprovisioned esxi disks miscellaneous knowledge. Vmware powercli script to list thin provisioned virtual disks.
Vmware esx 4 reclaiming thin provisioned disk unused space. Shrink a thinprovisioned vmdk if youve thinprovisioned a vmdk under esxi and need to reduce it for whatever reason, the official vmware documentation suggest to migrate the vm to another datastore using vmware converter which is not always practical, thankfully an alternative exists. May 20, 2014 before writing to a new block a zero has to be written, increasing the iops on new blocks compare to eager disks. Vmware admins also need to keep an eye on capacity alerts, because thinprovisioned vms grow over time. However, whilst thinprovisioned disks can semalessly grow themselves, they cannot be shrunk as easily. If youve cleaned up space on a thin provisioned disk and want to. Nov 07, 20 before we can use vmkfstools to shrink the vmdk file we must zero out any unused space on the thin provisioned disk. Thin provisioned disk shows 0kb size on the datastore even though it is a 40 gig disk the vmfs unmap operations inform the storage array that the blocks that it still has allocated as being in use are now able to be unmapped and the space reclaimed. Thick vs thin disks and all flash arrays vmware vsphere blog. Download sdelete onto the vm you want to shrink and run the following command, replacing drive.
The ugly truth about thin provisioning and the ntfs silent. Windows server thin provisioning features serve as interfaces between. Free up esxi local drive vmfs datastore space after deleting data in a thin provisioned windows vm. Esxi and array thin provisioning you can use thinprovisioned storage arrays with esxi. A simple way of doing this is by using a free utility called sdelete from sysinternals. Unfortunately, as you can see, thin vmdks only expand. Using sdelete and vmkfstools to reclaim thin vmdk space using thin provisioned virtual disks can provide many benefits. Once registered, you can download the ova and deploy to your virtual. In the vmware case, if you create a thin provisioned disk, its going to grow. Thin provisioning allows you to report more virtual storage space than there is real physical capacity. Before we can use vmkfstools to shrink the vmdk file we must zero out any unused space on the thin provisioned disk. Virtual disk thin provisioning when you create a virtual machine, a certain amount of storage space on a datastore is provisioned to virtual disk files. Vmware powercli script to list thin provisioned virtual disks vmdk one of my clients was concerned about the number of virtual machines that were built with thin provisioned disks. The ugly truth about thin provisioning and the ntfs silent treatment.
Please note that i dont want to focus on reclaiming space from underlaying luns. View virtual machine storage resources you can view how datastore storage space is allocated for your virtual machines. Demystifying vmware thin provisioning searchstorage. If a system always has enough resource to simultaneously support all of the virtualized resources, then it is not thin provisioned. When you work with a thin disk provisionned vm, you are copying new files into. The thin provisioned virtual disk starts small and grows as more disk space is required. Before they go with the project to inflate all thin provisioned disks or migrate to thick provisioned lazy zeroed they needed to know how much additional storage. Best practices for defragmenting thin provisioned storage 2 as data is added to a thin provisioned container, such as a dynamicthin virtual disk or a lun, that container increments, usually in a justintime basis, by a chunk or number of those chunks, depending on how many chunks are needed to house all the incoming writes.
How to limit the block usage on a thin provisioned vms vmware 0. A similar technique can be used to shrink thinprovisioned guest hard disks. How can i reduce thin provisioned allocation of vmdk that. Thin provisioning is a mechanism that applies to largescale centralized computer disk storage systems, sans, and storage virtualization systems. Reduce vmdk size the easiest method is to use vmware converter. For example, if you wrote 10gb of data to a thinprovisioned disk and then deleted it, although from the vms perspective the space is now free, from the perspective of the physical disk that the thinprovisioned vmdk is provisioned.
Below is an image which show what you will get in your shrink page of vmware tools if. Accessing the files direcly via scp or download via vspere client datastore will cause problems for thin provisioned files. Reclaim disk space from thin provisioned disks rickard nobel. To shrink a vmdk we can use an esx command line tool vmkfstools, but first you have to zero out any free space on your thin provisioned disk.
Thin provisioning is called sparse volumes in some contexts. Okay, lets try to storage vmotion the vm to another datastore and select thin provisioned format 3. Nov 24, 2014 having thin provisioned disk is usually no longer a performance problem so it is a valid design choice even in production. Vmware powercli script to list thin provisioned virtual. For a thin virtual disk, esxi provisions the entire space required for the disks current and future activities.
In virtual environments, there can even be a mix of both thin and thick provisioned storage. Since shrink was disabled for thin provisioned disk under windows 7 32bit, i have found an advice to run sdelete. If you allocated all the space for your virtual disk at the time. I first prepared the disk with sdelete c and sdelete z. Beware of these seemingly innocent vm tasks that can balloon a thin disk and wreak havoc on the it infrastructure. If you delete files from within the vm wanting to gain the space back, it just dont work. You may not be able to shrink the disk as small as you like, as windows creats a copy of the mft in the middle of the disk, and will not move it. Will thin provisioned vms shrink automatically just as they would grow automatically. To shrink a thinprovisioned vmdk the guest filesystem has to be zeroed out. Usedspacegb how much disk space is actually used by the vm. Thin provisioned disks are designed to expand and consume more disk space as the virtual machine requires.
Vmware vmdk shrink and storage thin provisioning 101. I am creating a brand new vm and specifying a 100gb thin provisioned hard disk. Before writing to a new block a zero has to be written, increasing the iops on new blocks compare to eager disks. Then you can storage vmotion the disk to a different data store changing it to thin provisioned, it will reclaim the unused space. Esxi and array thin provisioning you can use thin provisioned storage arrays with esxi. How to zero blocks in order to reclaim thin provisioned. Im only talking about shrinking thinprovisioned disks. A common issue with thin disks is that the size will grow when required, but never shrink. Aug 01, 2012 deleting data alone doesnt shrink a thinprovisioned disk. Reclaim disk space from thin provisioned vmdk files in esx by lunarg on december 12th 2014, at 12. You can create thin disks only on the datastores that support disklevel thin provisioning. Thin provisioning is an endtoend storage provisioning solution that offers justintime allocations.
If there is a large difference between the amount of data stored by the vm and the space consumed by the virtual disk file. Dec 24, 2016 having thin provisioned disk is usually no longer a performance problem so it is a valid design choice even in production. Thin provisioning allows space to be easily allocated to servers, on a justenough and justintime basis. Storage vmotion and moving to a thin provisioned disk. In computing, thin provisioning involves using virtualization technology to give the appearance of having more physical resources than are actually available.
A virtual guest drive could be thinprovisioned and the underlying storage could also be thin. When you work with a thin disk provisionned vm, you are copying new files into a vm, then deleting them, again and again, this process grow the thin disks over time. Zero free space using sdelete to shrink thin provisioned vmdk. The following script will identify all virtual machines with at least one thin provisioned disk, calculate the total size of configured virtual disks and then create a report of the disk usage and list all virtual disks helping you to identify which one of them is thin provisioned. I had downloaded a bunch of ova and iso files and had forgotten to move them over to a shared. Usually i use some zero fill utillity overwrite the free space in a think provisioned disk so virtualbox can shrink the disk. However, the thin disk uses only as much storage space as the disk needs for its initial operations. This disk, as all my disks for vms, was thin provisioned. Reclaim disk space from thin provisioned vmdk files in esxi server. Deleting data alone doesnt shrink a thinprovisioned disk. For example, if you create a new thin provisioned 30gb virtual disk and copy 10 gb of files to it, the size of the resulting vmdk file will be 10 gb, whereas you would have a 30gb vmdk file if you had chosen to use a thick provisioned disk. Mar 05, 20 shrinking a thick provisioned disk in vmware esxi 5. I have shrunk the volume within the vm to 250gb and have the rest as unallocated space. Storage vmotion back to the original datastore if desired.
So as alex pointed out, a thick provisioned file would be the result. Thin provisioning is a feature where the disk file increases over time. If there is a large difference between the amount of data stored by the vm and the space consumed by the virtual disk file it could be worth to reclaim the space. Nov 25, 2009 one more note before it comes up by my readers, vmware tools shrinking functionality is not support on thin provisioned disks. Since shrink was disabled for thinprovisioned disk under windows 7 32bit, i have found an advice to run sdelete. Jun, 20 thin provisioned storage can be used in 2 places. Space required for thin provisioned virtual disk is allocated and zeroed on demand as the space is used. How to shrink a vmdk using vmware converter techrepublic. Using thin provisioned virtual disks can provide many benefits. Thus i would recommend to export the virtual machine as an ovf file open virtualization format. This is the new thin provisioning stun vaai feature in vsphere 5. Thin provisioned virtual disks are quick to create and useful for saving storage space.
Shrinking thin provisioned asm disks results in smaller. The thin disks will start very small and grow as data is added within the vm, however if data is logically deleted inside the vm the thin disk will not shrink. The term thin provisioning is applied to disk layer in this article, but could refer to an allocation. Below is an image which show what you will get in your shrink page of vmware tools if you are using thin provisioned disk. Sep 24, 2016 however, whilst thinprovisioned disks can semalessly grow themselves, they cannot be shrunk as easily. Will thinprovisioned vms shrink automatically just.
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