dovecot IMAP with MS Outlook gives "The folder 'Inbox' cannot contain items" error - (2007.07.09)
We wanted the IMAP configs to work the way dovecot prefers, which is to make top-level folders
parallel to the inbox instead of nested under it. With one primary non-hidden namespace for
this, and a second hidden one that uses the "INBOX." prefix for compatability with courier-imap
and others, everything seemed great. That is, until someone used Microsoft Outlook (instead of
Outlook Express or our webmail client). For whatever reason, Outlook doesn't ask the server
about the inbox in subsequent runs, only when the account is first added, and instead makes
assumptions about how the inbox should be named. The result is that it worked the first time,
but the next time you'd run outlook you'd get the error "The folder 'Inbox' cannot contain items".
The above configuration is what fixed it. Before the correction, we had the inbox=yes in the first
of the two namespaces, not the second.
Compiling qmail and/or tcpserver/ucspi results in "/usr/bin/ld: errno: TLS definition in /lib/libc.so.6 section .tbss mismatches non-TLS reference in substdio.a(substdo.o) /lib/libc.so.6: could not read symbols: Bad value" error - (2007.11.30)
Rather distressing at first, but newer versions of glibc can result in this error. Since you may
be forced to recompile these programs due to a runtime error along the lines of "relocation error: /usr/local/bin/tcpserver: symbol errno, version GLIBC_2.0 not defined in file libc.so.6 with link time reference", you may find that you can't recompile
them as they are.
It turns out the solution is simple. No patching. Just add "-include /usr/include errno.h" in conf-cc, so that
the line looks like this:
cc -O2 -include /usr/include/errno.h
Opteron 270 CPU showing half speed in /proc/cpuinfo - (2009.12.03)
The problem was that not only was the CPU being displayed as half, but performance
characteristics showed this to be true, and not just a display issue. It turns out
it had nothing to do with BIOS or hardware, and was entirely due to linux.
I had just transitioned this machine to use CentOS 5.4 (based on RHEL 5.4), which
uses a service called "cpuspeed" which throttles the CPU based on perceived demand,
and for some reason on the Opterons this results in the CPU being left at half speed
even when under load. Googling around, I managed to find a couple of cases of people
running into this.
The fix is simple:
# service cpuspeed stop
# chkconfig cpuspeed off
... no need to even reboot.
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