I'm also seeing this issue replicated on 14.04.2 -
$ apt-cache show libc6 | grep Version Version: 2.19-0ubuntu6.11 Version: 2.19-0ubuntu6
$cat /var/log/apt/history.log
... Start-Date: 2017-03-21 07:11:13 Upgrade: libgnutls-openssl27:amd64 (2.12.23-12ubuntu2.6, 2.12.23-12ubuntu2.7), multiarch-support:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libfreetype6:amd64 (2.5.2-1ubuntu2.5, 2.5.2-1ubuntu2.6), libc-dev-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc6:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libgnutls26:amd64 (2.12.23-12ubuntu2.6, 2.12.23-12ubuntu2.7), libc6-dev:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10) End-Date: 2017-03-21 07:11:31 ...
Note some people suggesting a reboot will fix - in my case a reboot did not permanently fix the issue, but did give me around 18 hours of stability before performance was too poor to serve operationally.
I'm also seeing this issue replicated on 14.04.2 -
$ apt-cache show libc6 | grep Version
Version: 2.19-0ubuntu6.11
Version: 2.19-0ubuntu6
$cat /var/log/ apt/history. log
... openssl27: amd64 (2.12.23- 12ubuntu2. 6, 2.12.23- 12ubuntu2. 7), multiarch- support: amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libfreetype6:amd64 (2.5.2-1ubuntu2.5, 2.5.2-1ubuntu2.6), libc-dev-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc-bin:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libc6:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10), libgnutls26:amd64 (2.12.23- 12ubuntu2. 6, 2.12.23- 12ubuntu2. 7), libc6-dev:amd64 (2.19-0ubuntu6.9, 2.19-0ubuntu6.10)
Start-Date: 2017-03-21 07:11:13
Upgrade: libgnutls-
End-Date: 2017-03-21 07:11:31
...
Note some people suggesting a reboot will fix - in my case a reboot did not permanently fix the issue, but did give me around 18 hours of stability before performance was too poor to serve operationally.