I suddenly have +massive+ connection errors on the clients. Generally tvheadend is very slow, also in the web interface.
* I have tried resetting epg databases on client and server
* I checked my network, I can copy data back and forth to the server drive with no problem. Speed is high.
* I have tried both xbmc / kodi addons and vlc
I am stuck and would appreciate any help.

Don't hesitate to answer in German if easier for you!

Server: I am using tvheadend 3.4.27. It has been working fine for quite a while.

This is running on Ubuntu on an Intel Haswell server with a 4TB HDD for recordings and other media and a SSD for the OS.

As clients I have: openelec (I know this is old, but it worked for months)
XBMC (13.2-BETA2 Git:6d3bb09). Platform: x86 Linux 32-bit
OpenELEC (official) - Version: 4.1.2
* this has the default pvr addon, not pvr.tvh
Kodi 14.2 on Win7
* I tried both the default as also pvr.tvh downloaded today from http://stalin.negge.fi/files/pvr.tvh/

VLC on Win7

After deleting epgdb.v2 a reset of tvheadend shows this in syslog (comments are marked with <<<<<<<-------)

* The openelec client is running and will connect ASAP.
Reconnected to Tvheadend
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_dk_dr created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_eu_epgdata created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_fi created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_it created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_pt_meo created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_ee created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_es_laguiatv created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_pt created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_fr_kazer created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_in created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_es_miguiatv created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_no_gfeed created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_huro created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_fr created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_za created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_se_swedb created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_nl created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_na_dd created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_combiner created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_dtv_la created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_ar created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_hr created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_ch_search created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_uk_rt created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_fi_sv created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_uk_bleb created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_is created
Apr 01 23:32:38.473 epggrab: module /usr/bin/tv_grab_il created
Apr 01 23:32:38.474 dvr: Creating new configuration ''
Apr 01 23:32:38.550 START: HTS Tvheadend version 3.4.27~gfbda802~precise started, running as PID:4574 UID:106 GID:44, settings located in '/home/hts/.hts/tvheadend'

Apr 01 23:32:49.716 htsp: Got connection from 192.168.178.57

<<<<<<<<<<<---- the openelec client connects Apr 01 23:32:49.716 htsp: 192.168.178.57: Welcomed client software: XBMC Media Center (HTSPv8)
Apr 01 23:32:49.716 htsp: 192.168.178.57 [ XBMC Media Center ]: Disconnected
Apr 01 23:32:49.716 htsp: Got connection from 192.168.178.57
Apr 01 23:32:49.716 htsp: 192.168.178.57: Welcomed client software: XBMC Media Center (HTSPv8)
Apr 01 23:32:50.444 htsp: 192.168.178.57 [ XBMC Media Center ]: Identified as user tv
Apr 01 23:32:50.444 htsp: 192.168.178.57 [ tv | XBMC Media Center ]: Privileges raised
Apr 01 23:32:58.471 htsp: 192.168.178.57 [ tv | XBMC Media Center ]: Write error -- Broken pipe
Apr 01 23:32:58.476 htsp: 192.168.178.57 [ tv | XBMC Media Center ]: Disconnected
Apr 01 23:32:59.116 htsp: Got connection from 192.168.178.57
Apr 01 23:32:59.116 htsp: 192.168.178.57: Welcomed client software: XBMC Media Center (HTSPv8)
Apr 01 23:33:11.636 htsp: 192.168.178.57 [ XBMC Media Center ]: Identified as user tv
Apr 01 23:33:11.636 htsp: 192.168.178.57 [ tv | XBMC Media Center ]: Privileges raised

Apr 01 23:33:13.119 htsp: 192.168.178.57 [ tv | XBMC Media Center ]: Disconnected

<<<<<<<<<<<<<------ the Win7 kodi connects Apr 01 23:34:11.220 htsp: Got connection from 192.168.178.37
Apr 01 23:34:11.220 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:34:11.220 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:34:18.753 htsp: Got connection from 192.168.178.37
Apr 01 23:34:25.012 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:34:25.012 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:34:40.524 htsp: Got connection from 192.168.178.37
Apr 01 23:34:40.525 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:34:40.525 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:34:40.525 htsp: Got connection from 192.168.178.37
Apr 01 23:34:40.525 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:34:42.069 htsp: 192.168.178.37 [ XBMC Media Center ]: Identified as user tv
Apr 01 23:34:42.069 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Privileges raised
Apr 01 23:34:51.211 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Write error -- Broken pipe
Apr 01 23:34:51.216 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Disconnected
Apr 01 23:35:07.542 htsp: Got connection from 192.168.178.37
Apr 01 23:35:07.542 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:35:07.542 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:35:11.984 htsp: Got connection from 192.168.178.37
Apr 01 23:35:15.933 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:35:15.933 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:35:24.826 htsp: Got connection from 192.168.178.37
Apr 01 23:35:31.492 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:35:31.492 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:35:51.721 htsp: Got connection from 192.168.178.37
Apr 01 23:35:51.721 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:35:51.721 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:35:51.721 htsp: Got connection from 192.168.178.37
Apr 01 23:35:56.130 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:35:56.130 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:13.250 htsp: Got connection from 192.168.178.37
Apr 01 23:36:14.928 htsp: Got connection from 192.168.178.37
Apr 01 23:36:14.928 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:14.928 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:14.929 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:14.929 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:16.229 htsp: Got connection from 192.168.178.37
Apr 01 23:36:19.336 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:19.336 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:42.646 htsp: Got connection from 192.168.178.37
Apr 01 23:36:42.647 htsp: Got connection from 192.168.178.37
Apr 01 23:36:53.723 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:53.723 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:53.723 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:53.723 htsp: Got connection from 192.168.178.37
Apr 01 23:36:53.723 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:53.723 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:53.723 htsp: 192.168.178.37 [ XBMC Media Center ]: Disconnected
Apr 01 23:36:58.171 htsp: Got connection from 192.168.178.37
Apr 01 23:36:58.171 htsp: 192.168.178.37: Welcomed client software: XBMC Media Center (HTSPv12)
Apr 01 23:36:58.216 htsp: 192.168.178.37 [ XBMC Media Center ]: Identified as user tv
Apr 01 23:36:58.216 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Privileges raised
Apr 01 23:36:58.350 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Write error -- Connection reset by peer

Apr 01 23:36:58.350 htsp: 192.168.178.37 [ tv | XBMC Media Center ]: Disconnected

<<<<<<------------ vlc connects Apr 01 23:38:06.005 htsp: Got connection from 192.168.178.37
Apr 01 23:38:06.005 htsp: 192.168.178.37: Welcomed client software: VLC media player (HTSPv12)
Apr 01 23:38:08.852 htsp: 192.168.178.37 [ VLC media player ]: Identified as user tv
Apr 01 23:38:08.852 htsp: 192.168.178.37 [ tv | VLC media player ]: Privileges raised
Apr 01 23:38:30.393 htsp: Got connection from 192.168.178.37
Apr 01 23:38:36.556 htsp: 192.168.178.37: Welcomed client software: VLC media player (HTSPv12)
Apr 01 23:38:38.004 htsp: 192.168.178.37 [ VLC media player ]: Identified as user tv
Apr 01 23:38:38.004 htsp: 192.168.178.37 [ tv | VLC media player ]: Privileges raised

Apr 01 23:38:57.250 subscription: "192.168.178.37 [ tv | VLC media player ]" subscribing on "Das Erste HD", weight: 150, adapter: "Adapter2", network: "ASTRA 1", mux: "ASTRA 1: 11,493,750 kHz Horizontal (P19.2E)", provider: "ARD", service: "Das Erste HD", quality: 100

<<<<<<<--------- On Stopping the live TV in VLC: Apr 01 23:41:14.874 htsp: 192.168.178.37 [ tv | VLC media player ]: Disconnected
Apr 01 23:41:14.918 htsp: 192.168.178.37 [ tv | VLC media player ]: Write error -- Broken pipe

Apr 01 23:41:15.391 subscription: "192.168.178.37 [ tv | VLC media player ]" unsubscribing from "Das Erste HD"