Cyrus IMAP 2.4.14 released

Leena Heino Leena.Heino at uta.fi
Tue Mar 13 05:15:37 EDT 2012


On Tue, 13 Mar 2012, Bron Gondwana wrote:

> On Tue, Mar 13, 2012 at 10:31:08AM +0200, Leena Heino wrote:
>> I think making fulldirhash to use 64bit by default is a right thing
>> to do. But if we want a really fast fix then maybe the fulldirhash
>> 64bit change should be backed out.
>
> Personally I think throwing fulldirhash out with the trash is the
> right thing to do.  We use directory hashing at FM, though I'm
> tempted to think it's no longer required what with ext3's 32k
> folder limit gone away now.

We have to use fulldirhash because this way we are able to take backups 
more efficiently. The way Networker assings it resources makes it more 
efficient to use multiple directories that each have more or less the same 
amount of data and files.

> I can't see why a 32 bit hash isn't big enough though - it's no
> less random, and it's not expensive to calculate.

It is more about making the system work in a predictable way regardless 
the size of int in various tools and systems. The size of 32bit hash and 
the randomness it gives is most likely more than enough.

>> In order to make it really work in both pure or mixed 32bit and
>> 64bit environments the fulldirhash code in cyrus should look for the
>> data in both places. The tools/rehash script does that already.
>
> I think looking multiple places is the pragmatic fix.

I Agree.

-- 
   Leena Heino              University of Tampere / Computer Centre
   ( liinu at uta.fi )      ( http://www.uta.fi/laitokset/tkk )


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