Kmail over ssh extremely slow

I've got Kmail 4.14.1 working on my new Debian server (see topic "Can kmail still use a remote mail-store" - thanks iwolfi!) but it doesn't like ssh at all.
On my old server with Kmail 1.13.5 I always logged in from a laptop with "ssh -Y myserver" then typed 'kmail' and it worked perfectly at its normal speed - I never had a speed problem.
However, if I try this with the new server, Kmail 4.14 seems to try and load about three times, slowly, displays a message "The akonadi ... service is not running..." and a Start button, and then works so slowly as to be unusable. For example, clicking on a different sub-folder takes 6 seconds for the messages to appear in the list box. (Kmail works normally if started on the server itself).

It isn't a general network problem - both old and new servers are cable-connected off the same wireless router, both give ping times from my laptop of around 1ms, and if I ssh -Y into them from my laptop they both play the same video rather slowly on Mplayer. They're both using static DHCP with permanent IP numbers assigned in the wireless router.

Looking at the system monitors (and the activity light on my laptop's wireless card) seems to suggest that Kmail 4.14.1 is generating many times as much traffic as the old Kmail, per operation. Why or how I don't know.

However, in the terminal window at the start of pages of log text, it says:
"QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave."
It says the same in /var/log/messages if I start Kmail from the regular menu on the server. (But not on the old server).
I don't know if that's relevant.

Any suggestions for what to look for next would be welcomed.

Chris

The last warning is harmless.
As for the other, my guess is that is due to D-Bus traffic as many things moved out of KMail itself and on to specialized sub processes.

Thanks for the reassurance about the harmless warning.

My problem is, Kmail 4 is running so slowly over ssh and a wireless link as to be virtually unusable. If this is a feature of Kmail 4 (that didn't apply with Kmail 1.xx) then my previous way of working, which was to keep Kmail on my server downstairs and ssh in from whichever laptop I happened to be using in the comfort of my lounge, becomes impractical. I find it strange that displaying a new screen on Kmail actually needs so much two-way ssh traffic as to slow it down to that extent. Certainly that much traffic is currently being generated (my system monitor confirms it), I had hoped it was just some configuration fault. I would have expected that all Kmail's internal workings would take place on the server, and only screen outputs and keyboard inputs would reach my laptop, i.e. it would be functioning as just a terminal. But obviously not.

Maybe I need to do more research on how ssh works.

Cheers

Chris

Found it! By experimentation.
man ssh led me to the -C option, 'request compression of all data'

So long as I invoke ssh in a terminal window with

Code: Select all

ssh -CY myserver

then type 'kmail', Kmail 4 runs at a reasonable speed on my remote laptop.



cr