Volume snapshots disappearing?

[Barkley Bees]

I have deployed two identical servers (Storage Server 2003 R2 SP2 x64 - Dell
NF500 + MD3000) with DFS Namespaces and Replication and one shared folder on
the D: volume. This folder (Users) replicates between the two servers.

I have also configured Volume shadow copies on the D: volume of each server
and assigned 3.8TB for the shadow data (total volume is 10.9TB). I have
decided to keep the default schedule of 7am and 12pm for now.

Anyhow, for the first week or so it was taking snaps with no problem. Then
the other day I had about 10 pilot users copy their user folder data to the
new server (total ~12GB). All seemed well with replication working correctly
between the servers but then today I noticed that the volume snapshots are
disappearing which is quite dismaying to say the least. For the last two
days I am seeing the below in the event log:

--------------------------------------------------------------------------------------------------------------------
Event Type: Error
Event Source: VolSnap
Event Category: None
Event ID: 25
Description:

The shadow copies of volume D: were deleted because the shadow copy storage
could not grow in time. Consider reducing the IO load on the system or
choose a shadow copy storage volume that is not being shadow copied.
--------------------------------------------------------------------------------------------------------------------

I understand that under high IO load (as the error message states) that this
has been known to happen but this is with only 10 test users. We have
another file server (2TB of data) with VSS enabled and accessed by ~500-750
users that has never experienced this issue. It, like the new server, is
saving the volume snapshots to the same volume as the data.

I'm unsure as to what may be the actual cause here. Is it incorrect for me
to have VSS enabled on both servers that are replicating to each other (I
wouldn't think is related). Appreciate any advice or feedback from folks who
may have experience this or similar.

Note: I verified that disk write cache is not disabled.
http://support.microsoft.com/kb/826936 (several other similar kb's on the
matter but no clear resolution yet)

[HAL07]

I have also this problem, and it seem to be a common problem on all our fileservers. (Windows 2003 and 2003 R2's. 32bit)
This is not related to replication, but in general the filesystem that fails to grow.

I've tried resolving it several times, but I've never found time contacting Microsoft on it. So if you find a solution, please
post it! :)

Post by Barkley Bees
I have deployed two identical servers (Storage Server 2003 R2 SP2 x64 - Dell
NF500 + MD3000) with DFS Namespaces and Replication and one shared folder on
the D: volume. This folder (Users) replicates between the two servers.
I have also configured Volume shadow copies on the D: volume of each server
and assigned 3.8TB for the shadow data (total volume is 10.9TB). I have
decided to keep the default schedule of 7am and 12pm for now.
Anyhow, for the first week or so it was taking snaps with no problem. Then
the other day I had about 10 pilot users copy their user folder data to the
new server (total ~12GB). All seemed well with replication working correctly
between the servers but then today I noticed that the volume snapshots are
disappearing which is quite dismaying to say the least. For the last two
--------------------------------------------------------------------------------------------------------------------
Event Type: Error
Event Source: VolSnap
Event Category: None
Event ID: 25
The shadow copies of volume D: were deleted because the shadow copy storage
could not grow in time. Consider reducing the IO load on the system or
choose a shadow copy storage volume that is not being shadow copied.
--------------------------------------------------------------------------------------------------------------------
I understand that under high IO load (as the error message states) that this
has been known to happen but this is with only 10 test users. We have
another file server (2TB of data) with VSS enabled and accessed by ~500-750
users that has never experienced this issue. It, like the new server, is
saving the volume snapshots to the same volume as the data.
I'm unsure as to what may be the actual cause here. Is it incorrect for me
to have VSS enabled on both servers that are replicating to each other (I
wouldn't think is related). Appreciate any advice or feedback from folks who
may have experience this or similar.
Note: I verified that disk write cache is not disabled.
http://support.microsoft.com/kb/826936 (several other similar kb's on the
matter but no clear resolution yet)

[Barkley Bees]

Sadly, it has still been occurring on a daily basis. Here's my plan off
attack:

1. As a first step today, I have installed the following patch to the
secondary replication server:
Installed - KB943669
http://support.microsoft.com/default.aspx/kb/943669/en-us (will watch for
results and update)

2. If the above does not resolve the matter I will look at testing the
following: http://support.microsoft.com/default.aspx/kb/826936/en-us.
I will create a new registry entry "MinDiffAreaFileSize" in
"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VolSnap" and give it a
value of 3000 (3GB).

3. Then finally, if I must, I will reformat the drive to use 16k cluster
size (instead of the 4k default) as this is stated to be the best practice
when it comes to using VSS - http://support.microsoft.com/kb/312067/.

A very good reference here which I think pinpoints the problem:
http://duitwithsbs.wordpress.com/2008/07/21/drive-formatting-16k-cluster-to-avoid-loss-of-volume-shadow-copy-snapshots/

The strange thing is that another separate server (mentioned in my original
post) has been in use for over a year and is formatted using 4K cluster size
and never had this VOLSNAP EventID 25 occur once (never lost any snapshots).
Then again this new server is a fair bit larger in terms of capacity, using
Dynamic disks to span several large volumes, and also DFS-R.

Has anyone else been up this alley and found a valid solution? MVP folks
also?

Post by HAL07
I have also this problem, and it seem to be a common problem on all our
fileservers. (Windows 2003 and 2003 R2's. 32bit)
This is not related to replication, but in general the filesystem that fails to grow.
I've tried resolving it several times, but I've never found time
contacting Microsoft on it. So if you find a solution, please post it! :)

Post by Barkley Bees
I have deployed two identical servers (Storage Server 2003 R2 SP2 x64 -
Dell NF500 + MD3000) with DFS Namespaces and Replication and one shared
folder on the D: volume. This folder (Users) replicates between the two
servers.
I have also configured Volume shadow copies on the D: volume of each
server and assigned 3.8TB for the shadow data (total volume is 10.9TB). I
have decided to keep the default schedule of 7am and 12pm for now.
Anyhow, for the first week or so it was taking snaps with no problem.
Then the other day I had about 10 pilot users copy their user folder data
to the new server (total ~12GB). All seemed well with replication working
correctly between the servers but then today I noticed that the volume
snapshots are disappearing which is quite dismaying to say the least. For
--------------------------------------------------------------------------------------------------------------------
Event Type: Error
Event Source: VolSnap
Event Category: None
Event ID: 25
The shadow copies of volume D: were deleted because the shadow copy
storage could not grow in time. Consider reducing the IO load on the
system or choose a shadow copy storage volume that is not being shadow
copied.
--------------------------------------------------------------------------------------------------------------------
I understand that under high IO load (as the error message states) that
this has been known to happen but this is with only 10 test users. We
have another file server (2TB of data) with VSS enabled and accessed by
~500-750 users that has never experienced this issue. It, like the new
server, is saving the volume snapshots to the same volume as the data.
I'm unsure as to what may be the actual cause here. Is it incorrect for
me to have VSS enabled on both servers that are replicating to each other
(I wouldn't think is related). Appreciate any advice or feedback from
folks who may have experience this or similar.
Note: I verified that disk write cache is not disabled.
http://support.microsoft.com/kb/826936 (several other similar kb's on the
matter but no clear resolution yet)

[unknown]

We got the same problem on a Windows Unified Data Server 2003 SP2.

Did you succeed to solve the problem?

Thanks in advance!


EggHeadCafe - .NET Developer Portal of Choice
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[HAL07]

Post by unknown
We got the same problem on a Windows Unified Data Server 2003 SP2.
Did you succeed to solve the problem?
Thanks in advance!

Hi there,
the following patch seem to fix some of these issues: http://support.microsoft.com/?kbid=940349