Occasionally weird behaviour with mboxes

[Lorenzo Marcantonio]

It's some times a few user of mine lament a strange behaviour: they see
'gray' folders in thunderbird, but it happens *very* rarely... btw these
people have 6-10 GB of mail in their folders if it can be useful!

A protocol trace revealed that, indeed, the mbox is sent as noselect:

---------- crbrmt Tue May 18 08:52:24 2010

<1274165544<3 namespace
>1274165544>* NAMESPACE (("" ".")) (("Other Users." ".")) (("Shared Folders." "."))
3 OK Completed
<1274165544<4 list "" "%"
>1274165544>* LIST (\Noinferiors) "." "INBOX"
* LIST (\HasNoChildren) "." "APIndustria"
* LIST (\HasChildren) "." "Aziende"
* LIST (\HasNoChildren) "." "Bozze"
* LIST (\HasChildren) "." "Consulenti"
* LIST (\HasNoChildren) "." "Curriculum"
* LIST (\HasNoChildren) "." "Drafts"
* LIST (\HasChildren) "." "Fornitori A-F"
* LIST (\Noselect \HasChildren) "." "Fornitori G-Z"
* LIST (\HasNoChildren) "." "GEI"
* LIST (\HasNoChildren) "." "IN SOSPESO"

... so I presume that's the reason why it's shown in gray and the users
don't see the contents...

Other weird behaviour (possibly related) is that sometimes subfolders
'disappear' from the tree... closing and reopening the parent shows them
again; and from alpine sometimes saving messages gives a 'mailbox not
present', but retrying after a while works!

All off these are very spurious (I did a week of traces before seeing
the one shown before) but really annoying... what could be the reason?

It seems from a cursory look at the source that 'Noselect' is only for
'reserved' boxes (whatever they are) or am I missing something? Also
I see no errors in the logs and I assigned plenty of descriptors to
cyrus processes (65535); this is the second server I see this behaviour
on, so I would exclude flaky hardware...

Server is cyrus 2.3.14 on linux 2.6

Any idea/assistance could be useful


-- 
Lorenzo Marcantonio
Logos Srl