exchange 2003 cached transfer mode vs uncached

[Alex]

i know that one is 'online' and the other uses cached copies of emails etc but what are the advantages/disadvantages of each one...?

we have everything uncached over here at my company but i'm not sure that's the best option...

thanks!

 

[RebateMonger]

In cached mode, an updated version of the Exchange mailbox is kept on the local computer. If network connectivity is lost (the network goes down, the server goes down, or it's a laptop that's traveling), then local activity is stored in the cache and re-synchronized automatically upon reconnection to the Exchange Server.

Advantages:
1) As mentioned, disconnection from the server doesn't stop work and resynch upon reconnection is automatic.
2) The Outlook Junk Mail filter only works in cached mode. Messges are filter as they are written to the .OST cache.
3) When a User logs on, there's normally almost "zero" delay for email to syncrhonize, since the vast majority of email is already local.
4) Outlook is unaffected by "momentary" network glitches. When working in "non-cached" mode, these glitches can "freeze" Outlook temporarily.

Disadvantages:
1) The local cache (.OST) file requires local hard drive space. If there are multiple Users, space is used for each User.

Some modes of Outlook REQUIRE the Cached mode. Using Outlook with RPC over HTTPS requires Cached mode.

I've had zero issues with Cached mode and use it for all my clients.

 

[spyordie007]

I've got (just about) all our users running with Cached mode also.

The only "complaint" I sometimes see is that it can take a few extra seconds (up to 30 by default) for things to show up in your inbox. Of course you can always do a send/recieve to push things through immediatly or change this behavior if need be.

And of course:
http://support.microsoft.com/?id=870926

 

[Rilex]

2) The Outlook Junk Mail filter only works in cached mode. Messges are filter as they are written to the .OST cache.

We have users that are not in cached mode and the Junk Mail filter works just fine...

Cached Mode also creates the appearance of a more responsive Outlook since Outlook is sending mail every 30 seconds and retreiving every 15. A slow or unreliable link won't make Outlook "freeze up" or Requesting Data... (still happens, but not as nearly as bad).

 

[stash]

We have users that are not in cached mode and the Junk Mail filter works just fine...

This is correct...if you have Exchange 2003. Exchange 2000 requires cached mode Outlook for the Junk Filter to work.

 

[spyordie007]

Originally posted by: stash

We have users that are not in cached mode and the Junk Mail filter works just fine...

This is correct...if you have Exchange 2003. Exchange 2000 requires cached mode Outlook for the Junk Filter to work.

This is because Junk Email filtering can take place on the server in Exchange 2003. Just like Stash said if you run any other version of Exchange (or use a differant email server) you must be in cached mode.

More info:
http://www.microsoft.com/office/editions/prodinfo/junkmail.mspx
http://office.microsoft.com/en-us/assistance/HP052429671033.aspx

 

[FreshPrince]

all users with laptops should be on cache mode, no matter what. it just makes common sense.

for desktop users, we don't do cache mode for 1 reason only..and if anyone can help us out, maybe all our users can be on cache mode...

we're running everything 2003, exchange is 2003 enterprise:

pc's with cache mode turned on has a huge delay when updating the global address list...
if you add a new employee, it takes cache mode users a day or two to see the new user on the list. you can still email that user by manually typing out the email addy. for non-cache mode users, they see the new user right away. this is the only reason why we don't do cache mode for regular desktop users.

For users that are on the move all the time, they don't really care if they can't see new users in the GAL right away because most of the time, they're too busy running around to care

the other upside to cache mode is that you can reboot your mail server all you want now. users that are trained to use cache mode, don't get that pesky logon box when a server goes down. they can still work in outlook and write they emails. you don't get screem at either when that users writes a 50 page email and does not save it to draft...losing all they wrote when the server goes down. cache does not care, this is why I love it, and I wish I can implement it for all our users.

anyone know how to fix this?

 

[spyordie007]

I believe the default behavior of outlook clients is to only update their offline address book (OAB) once a day. You could alter the behavior and force Outlook to always do searches against your GAL by changing the registry key outlined here:
http://www.petri.co.il/gal_problems_and..._automatic_updates_in_outlook_2003.htm

However keep in mind that after making this change if they do not have connectivity to a GC they wont have access to the GAL (so you might only want to do it on the desktops).

EDIT: A bunch more information is available here about using the OAB:
http://www.microsoft.com/technet/prodte...l/exchange/2003/library/offlineab.mspx

 

[FreshPrince]

Originally posted by: spyordie007
I believe the default behavior of outlook clients is to only update their offline address book (OAB) once a day. You could alter the behavior and force Outlook to always do searches against your GAL by changing the registry key outlined here:
http://www.petri.co.il/gal_problems_and..._automatic_updates_in_outlook_2003.htm

However keep in mind that after making this change if they do not have connectivity to a GC they wont have access to the GAL (so you might only want to do it on the desktops).

good find!

we'll test that out

 

[Matthias99]

4) Outlook is unaffected by "momentary" network glitches. When working in "non-cached" mode, these glitches can "freeze" Outlook temporarily.

Lemme tell you, this is REALLY annoying. In Outlook 2003, at least, it freezes EVERY window (including emails you're typing, etc.) whenever it decides to go talk to the server and it doesn't respond right away.

if you add a new employee, it takes cache mode users a day or two to see the new user on the list. you can still email that user by manually typing out the email addy. for non-cache mode users, they see the new user right away. this is the only reason why we don't do cache mode for regular desktop users.

How often are you adding new employees/users?

 

[FreshPrince]

Originally posted by: Matthias99

4) Outlook is unaffected by "momentary" network glitches. When working in "non-cached" mode, these glitches can "freeze" Outlook temporarily.

Lemme tell you, this is REALLY annoying. In Outlook 2003, at least, it freezes EVERY window (including emails you're typing, etc.) whenever it decides to go talk to the server and it doesn't respond right away.

if you add a new employee, it takes cache mode users a day or two to see the new user on the list. you can still email that user by manually typing out the email addy. for non-cache mode users, they see the new user right away. this is the only reason why we don't do cache mode for regular desktop users.

How often are you adding new employees/users?

lately...about 1 a week...

but that's not the only thing...

if you create distribution list groups...same thing

if you create new global contacts...same thing (these are being added/deleted on a daily basis...)

so no, not just adding or removing employees...

 

[Tsaico]

Yeah, I have a similar problem with our users here, seem to have lots of additions and firings lately. What you are describing is a normal behavior though. You can do some things to help it out, as I think MS says it can take up to 72 hours to propegate in worst case scenario.

Any how, as the admin, you can force a rebuild of the Offline address book through the manager. The system does give you a warning that it can have a detrimental impact on your exchange performance, but I think that is at the enterprise level. With 200 users, i have notice no impact, and it is done within 5 min.

Then on the workstation you can force a download of the offline address book by goingin to the sen/receive menu and grab it from there.

Or you can wait...

We only have cached mode for the users with HUGE amount of mail (so browsing the folders is faster), which are only a handlful, plus all laptops and remote users. Good luck.

 

[RebateMonger]

Yeah, a User can have Outlook force a reload from the GAL. Otherwise, recently added users won't show up.

One of my clients has 20 desktops, all with 500MB to 2GB Exchange mailboxes, so Cached Mode really cuts down on network traffic for them.