Synchronous updates on ext3?

[Henrique de Moraes Holschuh]

On Thu, 29 Aug 2002, Lawrence Greenfield wrote:
>    Date: Thu, 29 Aug 2002 08:53:09 -0300
>    From: Henrique de Moraes Holschuh <hmh at debian.org>
> [...]
>    Don't try to second-guess the user. If anyone is dumb enough to enable
>    data=writeback in ext3, he deserves what he gets.
> 
> data=writeback is also safe, since Cyrus specifically calls fsync()
> before doing any crucial metadata operations.

Nice to know that :-)  So we can sum it up like this:

1. Cyrus needs that the filesystem metadata be kept sane, and that fsync()
is honoured.
2. Ext3 always does this, in all three modes of operation. Sync writes are
never needed.
3. Ext2 only does this in sync mode.

data=writeback might be slower than data=journal for ext3 mail spools. One
has to benchmark his particular fs, I suppose.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh