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Access 2003 Hates Jumbo Frames??
~400MB database on shared drive of computer A. Computer B is opening this database.
Consider the following:
Transfering the file from A to B is very fast with jumbos on or off -- though less CPU intensive with them on.
Working within the database is very slow with jumbos on and fast with them off. For instance, a compact and repair opperation that finishes in a matter of minutes with jumbos off takes 10 to 15 minutes with them on. With 6k packet size enabled during the Access operations there is almost no network activity and almost no CPU util -- which explains why it takes so long.
My question is why? Normal network use blazes with jumbo frames on my network. Only access seems to die.
jumbo frames are commonly associated with gigabit and typically range upward to 9000k. The biggest benefit is from lowering CPU utilization and perhaps slightly improving speed as well. You'll get problems if all the hardware doesn't support the larger frame/packet size and you try to use them. It works well for things like links between servers and over short, low latency connections. I think in your case given that not all the users with have gigabit and those that do may have hardware that only accepts standard frame size jumbos might be a bad idea.
This hotfix may or may not help with some of the delays: http://support.microsoft.com/default.aspx?scid=kb;en-us;894463.
BBraxton
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2037 Posts
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Posted May 24th, 2006 11:00
1) we use roaming profiles and invariably some students find their login takes so long (five or ten minutes) that it times out and they are issued a temporary desktop / profile. I can prevent this by unloaded masses of files being dragged around from PC to PC via the roaming.
2) mostly in writing using MS Word, there are episodes of as much as 30 seconds of "freezing" up. We have automatic synchronization set up but the active copy is (always) out on the (one) server. As I understand, the network was never intended to be a disk operating system but is forced to by our setup. When a user logs out, their new work and changes are copied down (synchronized) to the local PC. The reason for having the files out on the server is that they get backed up (Veritas) nightly.
I am wondering if #1 would benefit from Jumbo frames and #2 from "tiny" frames.
The thing I would suspect about threshhold (packet size) is that if one gets beyond a certain size, those that fail and have to be re-transmitted would more than offset the efficiency of the larger chunks (in the example of the COPY).
Maybe jumbo frames and packet sizes are two different animals.
Is Jumbo frames something peculiar to Gigabit (to which we are on the threshold of upgrading next two months)?
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