Comments on: Windows Guest Defragmentation, Take Two

By: Virtual Machine Guest OS Optimization « Pivot Point

Virtual Machine Guest OS Optimization « Pivot Point — Wed, 22 Jun 2011 09:51:00 +0000

[...] optimizations. The world of guest OS defragmentation is rich in this space with companies like my friends at PerfectDisk. But I’ve not yet seen anyone monitor and modify guest OS settings dynamically. While it [...]

By: VMware Linked Clone IO Implications « Pivot Point

VMware Linked Clone IO Implications « Pivot Point — Mon, 16 May 2011 10:07:36 +0000

[...] space that is available. I learned this from my friend Bob Nolan at PerfectDisk (Raxco) during our joint work on guest defragmentation over a year ago. This lazy placement produces fragmented files and free space, both of which harm [...]

By: Top 5 Planet V12n blog posts week 15 | Download VDI Solutions

Top 5 Planet V12n blog posts week 15 | Download VDI Solutions — Mon, 25 Oct 2010 18:41:11 +0000

[...] Drummonds - Windows Guest Defragmentation, Take TwoBefore I describe the test and its results, I want to share an important point on guest [...]

By: Set defragmentation schedules with Windows Server 2008 R2 | Servers and Storage | TechRepublic.com

Fri, 13 Aug 2010 13:29:58 +0000

[...] Another option to perform disk defragmentation is to use a third-party product such as Diskeeper, which has a new offering for virtual machine specific defragmentation and optimization with the V-locity product. Defragmentation in virtual machines is a topic that should not be ignored; in fact, former VMware employee Scott Drummonds wrote on the vPivot blog that a defragmented virtual machine can provide an amazing …. [...]

By: Defragmentimine ei ole virtuaalkeskkonnas mõistlik « Net Group Blog

Defragmentimine ei ole virtuaalkeskkonnas mõistlik « Net Group Blog — Thu, 27 May 2010 19:29:32 +0000

[...] poolest on tekkinud tarkvaratootjaid, kes tahavad defragmentimist rakendada ka virtuaalmasinates. Kindlasti leidub vastuargumente, kuid üldiselt arvan, et virtuaalmasinate defragmentimine on [...]

By: Paul H

Paul H — Mon, 03 May 2010 01:01:39 +0000

I too would like to see some more in-depth analysis with datastores on more “intelligent” SANs, such as NetApp, EMC, Equallogic. What impact would this have on de-dupe, load balancing, auto-tiering, etc.?

By: Mike Phelps

Mike Phelps — Sat, 24 Apr 2010 18:23:56 +0000

I’ve used Diskkeeper and Perfect disk for years. I switched exclusively to Perfect Disk in 2007 and haven’t looked back. I wondered about using v11 on our new virtual server about a month ago and took the plunge. It made a very noticeable difference immediately. I haven’t tried the boot-time scan, didn’t even think about it until just now, but I am happy with the results and will continue to use it on all of our servers and PC’s.

By: Samuel Brooks

Samuel Brooks — Sat, 24 Apr 2010 11:15:43 +0000

Thank you for your article and the information, it does give some guidence.

I would be interested to see what statistics look like in an larger scale environment where you have more HD’s in the RAID array to see how much is effected by HD Latency vs Fragmentation. With a (4) HUD with RAID 5 is going to have a different effect VS (8) HUD with RAID 5 or an iSCSI device with 14 HUD in a RAID 10 Array supporting the Had’s.

Consider running 15+ VHD’s per Host with (3) Hyper-V Host sharing Space in a CV environment. Are the Host communication between each other? I can see where a single host would keep check on it’s guest pretty easily but when you have multiple host sharing storage and the guest can transition between host due to fail over does it keep track of who is doing what to keep throttling of defrag activity in check?

By: Lenny Burns

Lenny Burns — Fri, 23 Apr 2010 22:27:22 +0000

I too feel that the benefit of guest defragmentation is there for many environements, but consider this warning CAREFULLY:

If you defrag guest VMs, in an environment that has a block-level de-duping storage system, one this is for sure, you WILL EXPLODE YOUR SAN DISK USAGE TO FULL SIZE!

Once you touch and move every block of every VMDK file, the blocks are now all unique again as far as your de-duping storage system sees things.

This causes the SAN to store each block again, as unique data and it must de-dupe all over again. (Assuming it can at this point).

For those that are counting on overbooking storage (liek NETAPP users do) you will fill your volumes and crash your envioronment at the SAN level.

For those that use thin provisioning, there are other considerations there too.

Defragmentation of guest VMDK files, in any environment that uses thin provisioning or block level de-duping strategies is a disaster in the making.

Be careful.

By: Ken

Ken — Fri, 23 Apr 2010 21:55:07 +0000

I don’t have hard evidence, but when we defragged our VM’s it made the world of difference with performance. I am a firm believer in defragmentation. On virtual machines absolutely. On Hosts hosting virtual machines? That is the bigger question. I would think that if you build a VM and use all of the space for that VM when you create it, there is lesser of a need to defragment the host, but if you allow the VM to consume the space as needed I could see that the host could become very fragmented quickly.

Just my two cents.