Link to home
Start Free TrialLog in
Avatar of poultarp
poultarp

asked on

Volume Shadow Copy and Page Pool memory

Hello Experts

Long story short.

We have a fileserver running Windows 2003 STD. SP2 32 bit.

The file server is hosting 2.5 million files.(1.1 TB data)
The server is set to Create Shadow copys 3 times a day.

Our server is suffering from Kernel memory page pool depletion. This gives us problems with insufficient system resources. That will make the system unable to handle big file transfers and user logons and RDP connections.

This is due to Volume Shadow Copy. As each snapshot we make steals about 2,5 MB of the page pool memory.

This is normal acording to this Technet article:

Scalability Factors for Shadow Copies
http://technet.microsoft.com/en-us/library/cc755419.aspx

Qoute:
That is why we estimate the paged pool memory usage as being between 1 MB and 2 MB per million files.
Qoute end

So this I understand. And i understand the limitations of the 32bit memory system.

But what i would like to know, is there anyway to limit the number of snapshot by count instead of by size?

I know I can set the size of the snapshot area, but it would be better if I could set the count?

say i would only allow 20 snap shots before the system removes the oldest one.

Can this be done?

This would allow me to control the Volume shadow copy service and prevent it for stealing all of the page pool memory.
Avatar of adolphus850
adolphus850

Hi Poultarp,

I do not have an answer for this but was wondering if you really need 3 shadows per day?  Also, do you have an appropriate antivirus on the server?  I have seen symantec slow the server down while it was doing its shadow copy.  Are you shadowing to a different drive?  Just some thoughts while someone comes up with an answer..

Adol
Avatar of poultarp

ASKER

Hello adolphus850.

We dont really need 3 shadows per day. But the number of shadows per day is irrelevant in my eyes.

if we get 40 shadows over a week or 40 shadows over a month, does not play a big difference.
The problems is when we reach too many shadows, we will get in trouble with our memory usage in the paged pool area.

The problems is not slow shadow copys, but for the record we use Symantec Endpoint on the server.
We are shadowing to the same drive as the data is on.

But again, the problem is not with creating shadows this works very good, but setting a limit is a problem.

The max size of a shadow copy area is not enough control for us.
hey poultarp:
just to share... we're having the same problem in our environment. 2 snapshots a day and we get maybe 10 snapshots before we starting having issues.  most common one that users' see for us is PST corruptions and the inability to copy/move large files due to lack of resources to perform the operation.  only difference we have is that we're shadowing to a diff volume (everything is SAN based) and we still have the same issue.

any update on your question?
I have the same issue. After 5-6 days the server starts rejecting connections and restarting the server is the only solution. When the problem starts the vssadmin list writers fails.
ASKER CERTIFIED SOLUTION
Avatar of rickardc
rickardc
Flag of United Kingdom of Great Britain and Northern Ireland image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
our conversations with Microsoft says the only way to get around the memory problem is to upgrade to 64-bit. apparently 64-bit does not have the same limitations to kernal and non-page pool memory.  of course this isn't an option for us at the moment so our fix is to scale back the number of snapshots and to cap the snapshots to a total of something like 25GB (even though the drive is like 200GB.
Problem was memory pool