I was surfing through my server manager, and I noticed a whole lot of yellow exclamation points on my server roles. After browsing them, I realized most were caused by the server reboot this morning, and can safely be deleted as 1 time events. I did notice an informational item under File Services.

Log Name:      System
Source:        volsnap
Date:          10/13/2010 12:00:34 PM
Event ID:      33
Task Category: None
Level:         Information
Keywords:      Classic
User:          N/A
Computer:      SOLACESERVER.solace.local
The oldest shadow copy of volume C: was deleted to keep disk space usage for shadow copies of volume C: below the user defined limit.

Server Manager and VSS Error Event ID 33

Server Manager and VSS Error Event ID 33

Configure Shadow Copies

Configure Shadow Copies

User defined limit? Did I set that? Oh well, let’s explore and see what it is set at, and how to gauge what the best settings are for a system. Navigate to Start>My Computer. Right click on the C: Drive and select Configure Shadow Copies.

I see four entries.





The first two are disabled. A:\ is my backup drive, and I do not it want Shadowed. The first is the volumename for my backup drive, which is also not Shadowed- why would you make copies of the drive that you store copies on, after all. If it WAS enabled, you could change it’s scheduling under scheduled tasks, Volume Shadow Copy. Were going to ignore those two for now- let’s focus on our two logical drives, C:\ and D:\. We do want these Shadowed- to provide previous version support for files, as well as for use in Windows Server Backup, which uses VSS.

These drives were both backed up today, they both have 10 shares, though the used size is different: 2088 for C:\, and 8921 on D:\. You will notice that both drives keep their own Shadow Copies. I at one time thought that this would be a good thing to change, so I put them both on a backup drive. Well, after that Windows Server Backup worked 50% of the time, and I could not change them back- exception error. So I suggest leaving them there.

Shadow Copies

Shadow Copies


But what about the size? Why are they different? Why does C:\ only have two copies while D:\ has 5? These settings are all set by Windows depending upon the drive size. My C: is 60Gb while D: is 90Gb. Also, D: has more content, and about the same free disk space. Proportionally the settings are correct- a large space for Shadow Copies on a larger drive. But C:\ is only keep two Shadow Copies, which gives you 2 previous version. You need more? Then increase the size by clicking settings and changing it.

You will notice in the settings menu that the limit is actually larger than the used- this is of course true. You can change it to no limit if you wish and have the space, or increase the limit to include many more copies. You can also change the schedule here- the default is twice a day. I like to leave mine here, though I change the times to make sure they do not run at the same time as other major things such as an Exchange backup.

In windows Server 2003 you had to keep the sizes as multiples of 300Mb, but this is no longer the case. As for the correct size- default is good. If you need it larger increase it untill you can keep the number of copies you wish. If you need it small, I suggest making it small incrementally, and make sure you can keep at lease 2 Shadow Copies. Making it too small might restrict Shadow Copies too much and interfere with Windows Server Backup.

You can also manage space and copies with the command line tool VSSADMIN, which is documented here at TechNet.