How to zero blocks in order to reclaim thin provisioned disk. 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. 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. When you have a lot of deletes within your vm you thinprovisioned san is unaware of this free space. Reducing the size of a thick provisioned vmdk without. 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. Reclaim disk space from thin provisioned vmdk files in esxi server.
How to zero blocks in order to reclaim thin provisioned. Lets say you have a base os install on a thin vmdk. The entire physical space needed to back each lun is allocated in advance. Guest reclaim reclaims dead space from ntfs volumes hosted on a thin provisioned scsi disk. Reclaim space on thin provisioning vmdk vmware communities. Using sdelete and vmkfstools to reclaim thin vmdk space. 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. This method contrast with thick provisioning and helps. We can use the dd utility to zero out the areas where the deleted data resides. The vmware kb article 20575 describes the command which reclaims the deleted blocks on an thin provisioned lun in vsphere 5. First, power off the affected vms and log into any esx server with access to the vmfs datastore which has the vmdks to shrink. To reclaim space on a windows vmdk, download sdelete to the local hard disk. Using veeam to reclaim space from thin provisioned vmdk post by dellock6 mon nov 17, 2014 11.
Making the most efficient use of the provisioned storage space is critical as well as reclaiming storage space that is no longer being used. Jul 03, 2012 yesterday a very cool fling was released. 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. Mar 30, 2015 if vmdk is thin provisioned you might want to shrink it back down again. How to reclaim disk space from a thin provisioned vmdk in. The tool can also reclaim space from full disks and partitions, thereby wiping off the file systems on it. Reclaim wasted capacity of vmdk files arab it network.
Vmware esx 4 reclaiming thin provisioned disk unused space. How to zero blocks in order to reclaim thin provisioned disk space with vmware storage vmotion red hat customer portal. The vmware kb article 20575 describes the command which reclaims the deleted blocks on an thinprovisioned lun in vsphere 5. In this example we have a thin provisioned vmdk file with the size of 8 gb. Vmdks in nfs environments are effectively files allocated directly on the networkattached storage appliance. However, the space might remain unused causing underutilization of storage capacity. Reclaiming thin provisioned storage space with vmware unmap. 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 have written some articles about dead space reclamation of the vmfs layer but this is about one layer up, the guest itself. 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 have a 16 tb thick provisioned disk but the vm is only using 9tb of this. Not only do they allow overprovisioning, but with the prevalence of flash storage, performance degradation really isnt a concern like it used to be. Using veeam to reclaim space from thin provisioned vmdk. When this happens we need to reclaim the deleted space using sdelete, which will just zero out the deleted space.
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. May 06, 2017 thin provisioned disks never shrink automatically when you delete data from it, lets learn how to do it. To look at more granular information about the amount of space consumed on the vmfs5. Nov 27, 2014 the esxi host which runs the reclaim would get very high cpu usage and might costops vms within the host. So first zero out the deleted space with sdelete and then use. So if you create a 10gb file and delete it, the user layer will still show that 10gb file is. How to reclaim unused space on thin provisioned disk with esxi 5. You can reclaim from within snapshots if they are sparase format used for vdi and vmdk s over 2tb for now. There are many different scenarios where this comes into play, and there many different ways to get the desired results. 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.
Download sdelete onto the vm you want to shrink and run the following. Reclaim disk space from thin provisioned vmdk files in esx by lunarg on december 12th 2014, at 12. Perfectstorage automatically reclaim space on thinprovisioned. Vaai thin provisioning block reclaimunmap in action. Jun 29, 2009 to reclaim space on a windows vmdk, download sdelete to the local hard disk. 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. For a thin virtual disk, esxi provisions the entire space required for the disks current and future activities, for example 40gb.
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. Lun space by sending scsi unmap reclaim commands to a vmware esxi. Storage vmotion the vm to another datastore and convert it to thin. When data has been deleted, youre ready to really reclaim disk space. Traditional luns that arrays present to the esxi host, are thick provisioned. A similar technique can be used to shrink thinprovisioned guest hard disks. The fundamental problem is that ntfs is a thin unfriendly file system it always writes into free space. 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. To shrink a thinprovisioned vmdk the guest filesystem has to be zeroed out.
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. I thought hey, this is weird, so i enabled ssh and logged in to check my volumes. Nfs data stores are by default thinly provisioned, so you dont need to create a vmdk with the thin attributes at create time. 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. Sometimes what your vm shows and your datastore shows are too different things.
Thin provisioning allows for on demand growth of a virtual. Release unused space on host and guest filesystems with thin. Reducing the size of a thick provisioned vmdk without vmotion. Reclaiming thin provisioned storage space with vmware.
The vmfs6 datastore can send the space reclamation command automatically. Shrinking vmdk is not possible, because thin disk allow us a feature to reclaim the unused space and not shrinking the vmdk. Using sdelete and vmkfstools to reclaim thin vmdk space using thin provisioned virtual disks can provide many benefits. The esxi host which runs the reclaim would get very high cpu usage and might costops vms within the host. And some space will be reclaimed in array as it is thin provisioned lun from storage. To look at more granular information about the amount of space consumed on the vmfs5 volume, we can use some cli commands. 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. 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. 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. The page reclaim disk space from thin provisioned disks talks about how to do that. To reclaim unused storage blocks on the thinprovisioned device, run the following command. If all went well you should now have a smaller vmdk file and newly reclaimed space. Perfectstorage reclaims space automatically on thinprovisioned disks, improving.
Vaai thin provisioning block reclaimunmap in action vmware. 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. Thin provisioned disks are a great feature to save capacity as you virtual machines filesystem will never use the full capacity. I am creating a brand new vm and specifying a 100gb thin provisioned hard disk.
This is required to reclaim space back from the virtual disk. Running sdelete with the following command will clear all lost space. Hyperflex does not have a mechanism for reclaiming space within a thin provision vm that is freed up. 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. In this example, the thinprovisioned disk occupies only 20gb of.
Reclaiming free space in thin provisioning vmware forum. On vmfs datastores that do not support automatic space reclamation, you can use the esxcli command to reclaim unused storage space manually. Reclaiming unused vmdk space with storage thin provisioning. You copy a 1gb file, now your os would report 16gb used and your vmdk grew also to 16gb. This feature is a great space saving technique, but rick vanover says its not worth the effort to constantly reclaim space. Here is a look at the provisioned and used space from a vmdk perspective.
This fling allows you to reclaim deadspace from a thin provisioned guest disk. Reclaim vmdk space on a thinprovisioned san behind the. When a lun is thin provisioned, the storage array reports the luns logical size, which might be. Sep 16, 2016 sometimes what your vm shows and your datastore shows are too different things. Unfortunately, i dont have any datastore with enough space on it for me to vmotion, copy, or clone the vmdk to. Release unused space on host and guest filesystems with. Vmdk file we must zero out any unused space on the thin provisioned disk. However, the thin disk uses only as much storage space as the disk needs for its initial operations. 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 space within a vm on a hyperflex cluster cisco. The command helps thin provisioned storage arrays to reclaim unused space from the vmfs datastore and thin virtual disks on the datastore.
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 thin provisioned space in vmware datastore 50mu. This is due to the inability of your thinprovisioned san to actually see inside the. Reclaim thin provisioned space punchzero thin provisioning of virtual disks has been a quiet benefit to it administrators working in virtual environments. I had downloaded a bunch of ova and iso files and had forgotten to move. How to release unused blocks from a thinprovisioned vmdk. Reclaim previously used space from a thick disk windows solution 1. 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. 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. Aug 01, 2011 vsphere 4 introduced thin provisioning of virtual machine disk files. Reclaim space within a linux vm on a hyperflex cluster. The command helps thinprovisioned storage arrays to reclaim unused space from the vmfs datastore and thin virtual disks on the datastore.
When you have a lot of deletes within your vm you thin provisioned san is unaware of this free space. This video shows perfectstorage running a reclaim operation in an esxhosted windows server 2008 guest in order to shrink a thinprovisioned vmdk. Reclaim disk space from thin provisioned disks rickard nobel. Reclaiming disk space with storage vmotion and thin. Dont waste time reclaiming space on thin provisioned vms. I do not know a single system where you do not have at least 10gb of free space for os disks. Im going to run space reclamation on a windows server 2008 r2 on a virtual machine called dc01ca01 and has the following storage characteristics. Once a block has been written to, it is always inuse even when you delete the file. Please note that i dont want to focus on reclaiming space from underlaying luns. If vmdk is thin provisioned you might want to shrink it back down again. I am not considering databases, applications or fileservers which will grow constantly. Once you download sdelete to the target vm, unzip the file. From all ive read, im expecting the physical size of the vmdk file to be less than 100gb.
Using veeam to reclaim space from thin provisioned vmdk post by dellock6. I see a lot of questions and answers surrounding thin provisioning on vmware esxi but not exactly what im encountering. Use the following command to zero out the empty space. 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. With the vmfs5 datastore, you can manually reclaim storage space. Zero free space using sdelete to shrink thin provisioned vmdk. Well start with a vm with a single thin provisioned disk. How to reclaim disk space from virtual machines with thin virtual disks in. Linux reclaim discard flag is not currently supported as only scsi2 commands only. 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. You can use thin provisioned storage arrays with esxi. This commandline tool has a powerful feature which can track and zero unused blocks.
A fairly simple process to reclaim thin provisioned vmdk space. Reclaim used space with vmkfstools punchzero buildvirtual. 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. This article will go over some options on reclaiming space within a thin provisioned vm that resides on hyperflex. 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.
Jan 12, 20 guest reclaim reclaims dead space from ntfs volumes hosted on a thin provisioned scsi disk. Recover lost space from thin provisioned disks by using. As the tool deals with active data, please take all precautionary measures understanding the scsi unmap framework and backing up important data. On windows guests we can use the sysinternals tool sdelete replace the drive. 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. Storage provisioning and space reclamation vmware docs. Reclaim space in a vm on thin or thick vmdks karims blog. Reclaim thin provisioned space punchzero vjourneyman. We havent talked about it just yet, as there is so much to cover. This deletion can come from either some type of application or the guest operating system. This is done by punching out zeroed blocks in the virtual disks vmdk file. This is due to the inability of your thin provisioned san to actually see inside the vmware vmdk format.
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