Jump to content
RESET Forums (homeservershow.com)

Slooooooow server backups with large files...


Recommended Posts

On one of our home servers we built we have been diagnosing a problem where the server backups would never complete successfully and we have tracked it down to the backup process taking forever when the backup set contains very large files.   We are careful to only included the servers C drive, the OS states, and only important shares from the server that we wish to back up. 


The backup basically runs all day... causing the next backup task to fail since the prior is still running.. Then after 24 hours the server gives up and kills the running backup (per the task scheduler rules of course).      If I exclude the one folder containing the large files (basically my collection of windows .isos) the server backup completes perfectly fine with the first finishing in < 30 minutes for a 400GB or so backup set.... But if I add in my 150GB share of .iso... That kills it every time...   Since the backups are incremental as a workaround I've simply started to add in the files 3 or 4 at a time so the next incremental backup picks them up....    Usually the next run would take 3 to 4 hours to finish and then the next time they go quick (as these files are never changing anyways).    Eventually I will have all the files properly backed up and not have to worry about it again unless I need to reinitialize the backup set again. 


We have checked to make sure the failure is not due to VSS, and it's not..


Has anyone seen this behavior or is there anything we can do to diagnose the poor backup performance... Or is this a known problem with the Windows 2008 R2 server backup solution..  

Link to comment
Share on other sites

Just to cover the bases, have you run a CHKDSK /F on the drive that holds the ISO files?


Yup, we did that diagnostics early on.    Even moved the share to another disk just to make sure it wasn't a physical error.   Its definitely the performance of Windows Server copying files into the .vhd image drops significantly if the file it's writing into the vhd is large...   I'm definitely leaning toward this is simply a shortcoming of Windows Server's self backup tool and have to find a more primitive backup tool to mirror my home server shares with critical data I want backed up...        Back to using synctoy, rsync, or maybe the new bittorent sync.

Link to comment
Share on other sites

You're backing up iso images?

In the example I used yes.. but it's not limited to .iso's...   One of the files that's problematic is I have a .vhd with an image of the Surface Pro recovery partition...  Obviously I want that backed up as there's no way to regenerate it if the media that's holding it is damaged.   There are valid use cases for having a backup set that may contain a large file or two that one would not like to lose...


Obviously, we exclude the recorded tv, client computer backups, podcasts, and the file history backup shares... Those shares already are the backup and the secondary copy... or as in the case of the recorded tv/podcast folder...   the data it too large and changes to frequently to be backed regularly and any loss would not be catastrophic.

Link to comment
Share on other sites

What AV program are you using?  What is different about this server form the others?  You mentioned server(s).


Have you looked at updating the NIC drivers or trying an alternate card or something like replacing a cable?  Just thinking out loud.

Link to comment
Share on other sites

All three server are running naked... No AV.


>What is different about this server form the others?

Hardware wise... Everything... these are all home brew system..  Software wise nothing....   Just stock home server.... no add ins.      However I'm only testing server backup on one of them.



>Have you looked at updating the NIC drivers or trying an alternate card or something like replacing a cable?

Nope, as this is the server backup that's running locally on the system and the backup drive is plugged in via USB 3.

Link to comment
Share on other sites

You said you made sure VSS is not the problem so the 13th post down in the following link doesn't help?





Have a simple workaround to this problem, finally!

1) You must configure the storage drive(s) to use an unlimited amount
of space for shadow volumes; this will allow it to go a much longer
interval before it chokes.  Procedure: my_computer->right-click the
drive->properties->shadow_copies tab->settings;
choose the no-limit radio button

2) when it does choke you blow away all the shadow volume copies and
it will work just fine again for a long while.  Procedure:
my_computer->right-click the drive->properties->shadow_copies
tab->disable; when it finished click enable
then ok. Shadow copies are now re-enabled with none hanging around.

3) I don't know if this third step helps or not, but I also
configured my drive to take only one volume snapshot a day instead of
two, configured my server backups to run at 4am only instead of twice a
day.  I configured the one volume snapshot to occur
12 hours away from the backup.  In my case it was always the 4am backup
that failed and the volume was configured to take a snapshot at 6am.  I
figure they bumped into one another.

Procedure: my_computer->right-click the
tab->settings->schedule->check "show multiple schedules"
box-> edit the schedule to be far far away in time from the scheduled

You're done!



Link to comment
Share on other sites

  • 1 year later...

Just to confirm, the solution presented by KydDynoMyte was correct.   The issues was the VSS limit for each drive was set to 5 GB and the backups were hanging on large files due to the VSS filling up and in some cases dying when the limit was reached.  Going in enabling the VSS service on each volume increased the VSS limit (used by both the previous version's and the backup feature) increased the size to 10% of the volume and things are much happier now.    Wondering why WHS 2011 leaves VSS off by default on shared drives.  

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...