This is done by punching out zeroed blocks in the virtual disks vmdk file. As the tool deals with active data, please take all precautionary measures understanding the scsi unmap framework and backing up important data. Running sdelete with the following command will clear all lost space. Reclaiming unused vmdk space with storage thin provisioning. Download a 30day free trial and see how easily you can reclaim space on. Nov 27, 2014 the esxi host which runs the reclaim would get very high cpu usage and might costops vms within the host.
Thin provisioning allows for on demand growth of a virtual. Well start with a vm with a single thin provisioned disk. On vmfs datastores that do not support automatic space reclamation, you can use the esxcli command to reclaim unused storage space manually. When a lun is thin provisioned, the storage array reports the luns logical size, which might be. Reclaim disk space from thin provisioned vmdk files in esx dec 12 2014 by lunarg at black manticore i was now confident enough that sdeletevmkfstools combo was likely to work out, and looked more appealing than the prior tinkering i had done with the much more complicated cbt method that required many steps and tools, for my much larger. Nfs data stores are by default thinly provisioned, so you dont need to create a vmdk with the thin attributes at create time. Thin provisioned disks are a great feature to save capacity as you virtual machines filesystem will never use the full capacity. How to shrink a thin provisioned virtual disk vmdk thin provisioned disks are a great feature to save capacity as you virtual machines filesystem will never use the full capacity. Sep 16, 2016 sometimes what your vm shows and your datastore shows are too different things. Reducing the size of a thick provisioned vmdk without. Use the following command to zero out the empty space.
This is required to reclaim space back from the virtual disk. Linux reclaim discard flag is not currently supported as only scsi2 commands only. Jun 30, 2017 reclaim thin provisioned space in vmware datastore posted by rob koper on june 30, 2017 leave a comment 0 go to comments we were using a portable storage array as temporary storage array to store data from an older array that had to be reconfigured. I am not considering databases, applications or fileservers which will grow constantly. To shrink a thinprovisioned vmdk the guest filesystem has to be zeroed out. Guest reclaim reclaims dead space from ntfs volumes hosted on a thin provisioned scsi disk. When data has been deleted, youre ready to really reclaim disk space. Reclaiming thin provisioned storage space with vmware. With the virtualized file systems that are utilized by hypervisors today such as vmwares vmfs, there is a layer of abstraction from the physical hardwares knowledge of how much storage is in use and. Reclaim space on thin provisioning vmdk vmware communities.
This fling allows you to reclaim deadspace from a thin provisioned guest disk. We have covered so far the vcenter upgrades, esxi upgrades via isocdrom, but also via vmware online depot or via offline bundle note that you can find all posts about vsphere 6. Reclaim vmdk space on a thinprovisioned san behind the. Making the most efficient use of the provisioned storage space is critical as well as reclaiming storage space that is no longer being used. The fundamental problem is that ntfs is a thin unfriendly file system it always writes into free space. The entire physical space needed to back each lun is allocated in advance. In this example we have a thin provisioned vmdk file with the size of 8 gb. Vaai thin provisioning block reclaimunmap in action. I am creating a brand new vm and specifying a 100gb thin provisioned hard disk. Reclaim thin provisioned space punchzero vjourneyman. You can use thin provisioned storage arrays with esxi.
This method contrast with thick provisioning and helps. Please note that i dont want to focus on reclaiming space from underlaying luns. Shrinking vmdk is not possible, because thin disk allow us a feature to reclaim the unused space and not shrinking the vmdk. Nov 24, 2014 howto shrink a thin provisioned virtual disk vmdk posted by fgrehl on november 24, 2014 leave a comment 25 go to comments thin provisioned disks are a great feature to save capacity as you virtual machines filesystem will never use the full capacity. If vmdk is thin provisioned you might want to shrink it back down again. First, power off the affected vms and log into any esx server with access to the vmfs datastore which has the vmdks to shrink. When you have a lot of deletes within your vm you thinprovisioned san is unaware of this free space.
To reclaim space on a windows vmdk, download sdelete to the local hard disk. Reclaim previously used space from a thick disk windows solution 1. I thought hey, this is weird, so i enabled ssh and logged in to check my volumes. Download sdelete onto the vm you want to shrink and run the following. How to reclaim unused space on thin provisioned disk with esxi 5. I have a 16 tb thick provisioned disk but the vm is only using 9tb of this.
Reclaim thin provisioned space in vmware datastore posted by rob koper on june 30, 2017 leave a comment 0 go to comments we were using a portable storage array as temporary storage array to store data from an older array that had to be reconfigured. Im going to run space reclamation on a windows server 2008 r2 on a virtual machine called dc01ca01 and has the following storage characteristics. Reclaim thin provisioned space in vmware datastore 50mu. Yes we used to have a work around of inguest reclamation of blocks by using sdelete and storage vmotion but due to the vaai offloading. There are many different scenarios where this comes into play, and there many different ways to get the desired results. Perfectstorage automatically reclaim space on thinprovisioned. How to shrink a thin provisioned virtual disk vmdk. As your datastore grows or if you use storage vmotion to migrate virtual machines to a thinprovisioned lun, the host communicates with the lun and warns you about breaches in physical space and about outofspace conditions. This is due to the inability of your thinprovisioned san to actually see inside the. Mar 30, 2015 if vmdk is thin provisioned you might want to shrink it back down again.
When you have a lot of deletes within your vm you thin provisioned san is unaware of this free space. Looking at its size on the datastore remember to use du rather than ls to get the true size we can see that it is currently using 1. Lun space by sending scsi unmap reclaim commands to a vmware esxi. The vmfs6 datastore can send the space reclamation command automatically. Reclaiming thin provisioned storage space with vmware unmap. The esxi host which runs the reclaim would get very high cpu usage and might costops vms within the host. To look at more granular information about the amount of space consumed on the vmfs5.
On windows guests we can use the sysinternals tool sdelete replace the drive. Vmdk file we must zero out any unused space on the thin provisioned disk. This video shows perfectstorage running a reclaim operation in an esxhosted windows server 2008 guest in order to shrink a thinprovisioned vmdk. Thin provisioning space reclamation issues with vsphere. The tool can also reclaim space from full disks and partitions, thereby wiping off the file systems on it. Using sdelete and vmkfstools to reclaim thin vmdk space using thin provisioned virtual disks can provide many benefits. The vmware kb article 20575 describes the command which reclaims the deleted blocks on an thinprovisioned lun in vsphere 5.
If all went well you should now have a smaller vmdk file and newly reclaimed space. The document solution to reclaim the free space also in the vmfs is fill the free blocks in the guest os with zeroed on windows can be done with sdelete and on linux with dd and then use a storage migration cold or hot with storage vmotion to move the vm file from one datastore to another. Reclaim disk space from thin provisioned vmdk files in esx by lunarg on december 12th 2014, at 12. Reclaiming free space in thin provisioning vmware forum. We can use the dd utility to zero out the areas where the deleted data resides. Hyperflex does not have a mechanism for reclaiming space within a thin provision vm that is freed up. In this example we have a thin provisioned vmdk file with the size of 8 gb, which is the size of the disk as it appears to the virtual machine, in this case a windows 2003 server. Reclaim thin provisioned space punchzero thin provisioning of virtual disks has been a quiet benefit to it administrators working in virtual environments. Storage vmotion the vm to another datastore and convert it to thin.
However, the thin disk uses only as much storage space as the disk needs for its initial operations. 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. I see a lot of questions and answers surrounding thin provisioning on vmware esxi but not exactly what im encountering. Reclaim wasted capacity of vmdk files arab it network. Reclaim disk space from thin provisioned vmdk files in esxi server.
Dec 05, 2011 the document solution to reclaim the free space also in the vmfs is fill the free blocks in the guest os with zeroed on windows can be done with sdelete and on linux with dd and then use a storage migration cold or hot with storage vmotion to move the vm file from one datastore to another. This article will go over some options on reclaiming space within a thin provisioned vm that resides on hyperflex. May 06, 2017 thin provisioned disks never shrink automatically when you delete data from it, lets learn how to do it. You can reclaim from within snapshots if they are sparase format used for vdi and vmdk s over 2tb for now. 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. The command helps thin provisioned storage arrays to reclaim unused space from the vmfs datastore and thin virtual disks on the datastore. Reducing the size of a thick provisioned vmdk without vmotion. Reclaim disk space from thin provisioned disks rickard nobel. To reclaim unused storage blocks on the thinprovisioned device, run the following command. So first zero out the deleted space with sdelete and then use. Jan 12, 20 guest reclaim reclaims dead space from ntfs volumes hosted on a thin provisioned scsi disk. I had downloaded a bunch of ova and iso files and had forgotten to move. And some space will be reclaimed in array as it is thin provisioned lun from storage.
Once you download sdelete to the target vm, unzip the file. Jun 02, 2014 this video shows perfectstorage running a reclaim operation in an esxhosted windows server 2008 guest in order to shrink a thin provisioned vmdk. How to zero blocks in order to reclaim thin provisioned disk space with vmware storage vmotion red hat customer portal. Using veeam to reclaim space from thin provisioned vmdk post by dellock6. Reclaim space within a vm on a hyperflex cluster cisco.
Once a block has been written to, it is always inuse even when you delete the file. Jan 24, 2011 reclaiming disk space with storage vmotion and thin provisioning ive seen a number of posts on the vmtn forums as well as had discussions with folks regarding reclaiming disk space with storage vmotion so i thought it made sense to do a quick writeup on how this process works. Using veeam to reclaim space from thin provisioned vmdk. 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.
This commandline tool has a powerful feature which can track and zero unused blocks. Reclaiming disk space with storage vmotion and thin provisioning ive seen a number of posts on the vmtn forums as well as had discussions with folks regarding reclaiming disk space with storage vmotion so i thought it made sense to do a quick writeup on how this process works. Using veeam to reclaim space from thin provisioned vmdk post by dellock6 mon nov 17, 2014 11. Not only do they allow overprovisioning, but with the prevalence of flash storage, performance degradation really isnt a concern like it used to be. With the vmfs5 datastore, you can manually reclaim storage space. Reclaim space within a linux vm on a hyperflex cluster. You copy a 1gb file, now your os would report 16gb used and your vmdk grew also to 16gb. Reclaiming disk space with storage vmotion and thin. Note however that the process writes to the vmdk as it goes, so make sure you have enough free space on your datastore for the full disk. Perfectstorage reclaims space automatically on thinprovisioned disks, improving. When this happens we need to reclaim the deleted space using sdelete, which will just zero out the deleted space. This feature is a great space saving technique, but rick vanover says its not worth the effort to constantly reclaim space. From all ive read, im expecting the physical size of the vmdk file to be less than 100gb.
I have written some articles about dead space reclamation of the vmfs layer but this is about one layer up, the guest itself. Reclaim used space with vmkfstools punchzero buildvirtual. Vmware esx 4 reclaiming thin provisioned disk unused space. Monitor the use of space on thinprovisioned luns to avoid running out of physical space. Jun 29, 2009 to reclaim space on a windows vmdk, download sdelete to the local hard disk.
Aug 01, 2011 vsphere 4 introduced thin provisioning of virtual machine disk files. Reclaim space in a vm on thin or thick vmdks karims blog. Vaai thin provisioning block reclaimunmap in action vmware. For a thin virtual disk, esxi provisions the entire space required for the disks current and future activities, for example 40gb.
Dont waste time reclaiming space on thin provisioned vms. Recover lost space from thin provisioned disks by using. How to zero blocks in order to reclaim thin provisioned. The page reclaim disk space from thin provisioned disks talks about how to do that. Vmdks in nfs environments are effectively files allocated directly on the networkattached storage appliance.
Storage provisioning and space reclamation vmware docs. Zero free space using sdelete to shrink thin provisioned vmdk. This deletion can come from either some type of application or the guest operating system. Unfortunately, i dont have any datastore with enough space on it for me to vmotion, copy, or clone the vmdk to. Jul 03, 2012 yesterday a very cool fling was released. How to zero blocks in order to reclaim thin provisioned disk. The command helps thinprovisioned storage arrays to reclaim unused space from the vmfs datastore and thin virtual disks on the datastore.
We havent talked about it just yet, as there is so much to cover. A similar technique can be used to shrink thinprovisioned guest hard disks. Nov 09, 2015 reclaim disk space from thin provisioned vmdk files in esx dec 12 2014 by lunarg at black manticore i was now confident enough that sdeletevmkfstools combo was likely to work out, and looked more appealing than the prior tinkering i had done with the much more complicated cbt method that required many steps and tools, for my much larger. Reclaim space within a linux vm on a hyperflex cluster introduction this article will go over some options on reclaiming space within a thin provisioned vm that resides on hyperflex. Traditional luns that arrays present to the esxi host, are thick provisioned. When you delete data on thinprovisioned disks, the physical size of the vmdk file for the disk remain the same as before deleting the data, thinprovisioned disks grow in one direction, but doesnt shrink automatically, and this is a big issue for vsphere admins. How to reclaim disk space from a thin provisioned vmdk in. Possibly the biggest issue that we have with thin provisioning is running out of space on a device that is thin provisioned at the backend. A fairly simple process to reclaim thin provisioned vmdk space. Im only talking about shrinking thinprovisioned disks. Sometimes what your vm shows and your datastore shows are too different things. 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.
I do not know a single system where you do not have at least 10gb of free space for os disks. Using sdelete and vmkfstools to reclaim thin vmdk space. How to zero blocks in order to reclaim thin provisioned disk space with vmware storage vmotion. I run a sophos utm firewall appliance in my vmware vsphere environment and noticed the other day that i was getting warnings on the space used on the esxi host for the thinprovisioned vmdk file for the guest vm. I read a comment where someone mentioned using sdelete to zero out the unused blocks, powering down the vm, and then using the vmkfstools punchzero command to convert the disk from thick. How to reclaim disk space from virtual machines with thin virtual disks in. So if you create a 10gb file and delete it, the user layer will still show that 10gb file is. In the recent past of thick provisioned storage as the only option still common in nonvirtualized, local storage environments, administrators made educated guesses about the amount of. This is due to the inability of your thin provisioned san to actually see inside the vmware vmdk format.
In this example, the thinprovisioned disk occupies only 20gb of. How to release unused blocks from a thinprovisioned vmdk. However, the space might remain unused causing underutilization of storage capacity. The vmware kb article 20575 describes the command which reclaims the deleted blocks on an thin provisioned lun in vsphere 5. Release unused space on host and guest filesystems with thin. To look at more granular information about the amount of space consumed on the vmfs5 volume, we can use some cli commands. Here is a look at the provisioned and used space from a vmdk perspective.
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