Warning: Disk Deframenters can "ruin" System Restore

[ky331]

Volume Shadow Copy is a service that creates and maintains snapshots ("shadow copies") of disk volumes in Windows 7 and Vista. It is the "back-end" of the System Restore feature.

In the event disk I/O becomes "excessive", it can "overwhelm" the Shadow Copy process, generating a "VolSnap Error":
Event-ID 25: Volsnap. The shadow copies of volume C: were deleted because the shadow copy storage could not grow in time.

And since System Restore resides within the Shadow Copy Service area, the result of a VolSnap Error can be the total loss of all System Restore points!

Under most normal usage, this shouldn't happen.  But I've recently discovered a major exception:  Disk Defragmenters.

Some disk defragmenters have become so "timewise efficient" at their task of moving data around that the resulting volume of I/O processed is sufficiently massive & fast so as to cause a VolSnap error!

I have been using Auslogics Disk Defrag (Free) for many years now, and have been happy with the results. I never had any issue with it on WinXP --- which does not have a Volume Shadow Copy service. And while unfortunately, I have regularly been a victim of "disappearing" System Restore points on one of my Win7 systems, I never understood why --- until now: The excessively-"efficient" RATE of disk I/O during Auslogic's defragging process generated VolSnap errors, deleting the "shadow copies" of my C: drive, thereby eradicating all my System Restore points  :shock: .

Fortunately, there is a simple solution in this particular case: start the Auslogics program, select SETTINGS, then PROGRAM SETTINGS, the ALGORITHMS tab, CHECK the box to "Defragment in VSS compatible mode", and click OK.   Hopefully, that has fixed the issue for me... only time will tell.

It seems the impact of checking this box is for Auslogics to run at a more "moderate" pace: for example, it may now take two or three minutes to defrag the disk, rather than one. But if this minor slowdown can keep System Restore "alive", it's definitely worth it.

Please emphasize that this should not be viewed as a specific condemnation of the Auslogics program, as my understanding is that several other disk defragmenters can likewise have the same negative impact. So if any of you ever encounter the issue of System Restore points mysteriously "disappearing", this is one possible cause that you should be aware of, to take into consideration.

[Disclaimer: On a separate note, I believe Joe53 stopped using Auslogics due to some PUPs that recent versions/installers have included, which inadvertently got installed on his system.   Always be sure to read-through the various installation screens of ANY program, keeping an eye-out for any boxes/offers (be they pre-checked or unchecked!]

[winchester73]

Further reading:  http://support.microsoft.com/kb/312067

For those who blame third-party defragmenters, it appears even the built-in Windows version can cause problems:  http://answers.microsoft.com/en-us/windows/forum/windows_7-performance/windows-7-defrag-is-deleting-restore-points/7c402ac1-a4a0-4434-a890-a60a5d51f4bb

I use the Auslogics program on this Vista box, with the VSS-compatible mode ticked, and have never lost any restore points.

Trick #3 here:  http://www.auslogics.com/en/articles/how-to-defrag/

[Digerati]

This has been documented quite a bit in the past and I believe it is just another reason to use Windows own defragger (now called Optimize Disk) instead of 3rd party defraggers - as well as proper user "preventative maintenance".

For those who blame third-party defragmenters, it appears even the built-in Windows version can cause problems

True, but IMO, 3rd party defraggers are just a waste of disk space. Which is ironic, if you consider defragging is supposed to optimize that same space. And insufficient amounts of free disk space is the issue here.

By design, System Restore will automatically delete Restore Points and reduce its own footprint when resources (read: free disk space) becomes limited. Defraggers while defragging, by design, consume HUGE amounts of disk space (though temporarily) while moving file segments about in the process of putting them in sequential order.

It is during the defragging process when massive amounts of disk space is used, forcing SR to delete points - on drives that are crowded in the first place.

This problem, from all that I have read, does not happen when the drive has gobs of free space available.

Sure, after market defraggers can squeeze out a few extra percentage points in defragging efficiency, but so what? The second, and I mean that quite literally, the second you start to use your computer again after defragging, fragmentation starts all over again. So any advantage is quickly negated.

The simple facts are (1) most users only need "basic" tools. (2) Windows integrated tools such as Optimize Disk (the real name of Windows defragger) is a basic tool. Therefore, (3) most users don't need 3rd party tools.

And (4) it is the user's responsibility to ensure his or her drives have sufficient free space for "Windows" and defraggers to operate in. This means BEFORE free disk space drops to critical levels, the user has the responsibility to free up space by keeping clutter at bay, by uninstalling unused user-installed programs and/or by buying more disk space.

Please emphasize that this should not be viewed as a specific condemnation of the Auslogics program,

Same here. I used to use Auslogics, then Defraggler (from the makers of CCleaner). Great tools - but I don't need them. The basic tool in Windows is all we need - ESPECIALLY if I am defragging to free up and optimize available disk space.

That said, I have a problem with ANY defragging utility that defrags in real-time or via a schedule. So that means I have a problem with Windows Optimize Disk tool too. Why? Because it is counter-productive and inefficient to defrag a drive with potentially many 1000s of tiny temporary files on the disk. Therefore, you should ALWAYS clean the clutter with Windows Disk Cleanup - another fine, "basic" tool in all versions of Windows. But real-time defraggers and scheduled defraggers don't do that.

There is another reason to use the native Windows tool in W7, and especially in W8. ONLY Windows Optimize Disk works with Windows "prefetch" routines to optimize the programs YOU USE regularly on your "hard" disks during defragging so they will load faster. Note the prefetch features are disabled on SSDs, but then so is defragging. Optimize Disk in W8.x only trims SSDs.

[ky331]

Just to mention/clarify a few points:
1) My hard drive has at least 85% FREE space available, so it was not a matter of "overdriving" the defragger because of insufficient free space to do its job.
2) I always run CCleaner first, to remove all the temp-file "clutter", prior to defragging. 
Additionally, Auslogics includes an option [which I have checked/enabled] to "Delete temporary files before defragmenting".
3) I am using Auslogics only for its basic mechanism to defrag individual files (bring all its pieces contiguously together).   On the machine in question, I was NOT using the "advanced" procedure to "optimize" the disk by rearranging ALL the files [to remove embedded "whitespace/gaps" (which offers the further option to move all System files to the "beginning" of the disk)].

[Digerati]

1) My hard drive has at least 85% FREE space available, so it was not a matter of "overdriving" the defragger because of insufficient free space to do its job.

Percent does not tell us much without knowing how big the whole drive is, but for sure, I like to keep at least 30Gb free - especially on the boot drive - to give Windows lots of elbow room for temp files, Windows Updates, the Windows Managed Page File, Optimize Disk, and Windows itself to operate in.

Secondary drives don't need as much free space, unless the user has moved the Temporary File folder location and PF to the secondary drive.

Don't know what you mean by "overdriving" the defragger. You can certainly put excessive work on a hard drive if the disk is full and/or excessively fragmented, but that does not "overdrive" the defragger.

I always run CCleaner first.

So do I. But if a client or poster is trying to defrag the drives to make more free space, I don't recommend downloading and installing yet another program that consumes even more precious disk space. So Windows Disk Cleanup, while a "basic" cleaner, is perfect for that because it is already on everyone's system.

(which offers the further option to move all System files to the "beginning" of the disk)].

Years ago, moving the system files to the beginning of the disk made sense. But not today - not when Windows Update is constantly updating many of those files. Optimize Disk in W7 and especially in W8 will place other program files at the beginning, if you, the user, use them frequently to speed up loading of your favorite programs.

[Aaron Hulett]

You do not need to run defrag, whether built in or third party, on newer versions of Windows. The OS manages this on its own and is best left alone.

[Digerati]

I agree with Aaron. The folks at MS have been fine tuning the process based on many years of statistical data on how to do it best. And IMO, they have it figured out with each new version of Windows having yet a better integrated solution.

As another reminder, we MUST remember that W7 and especially W8 are NOT Windows XP. So we need to stop assuming what was needed then is needed today - it most likely is just not true!