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Re: xfs, reiserfs, ext2 and sync directory updates

On Thu, Jul 19, 2001 at 09:19:29PM -0400, Bulent Murtezaoglu wrote:
> Hmm.  I beg to differ.  I expect people I buy infrastructure from to
> care about not losing mail.  If the daemon 250's the DATA in the SMTP
> conversation it should guard it with more than its life.  In an ideal
> world.

i care a lot about not losing mail. i would take it as a personal
failing if it ever happened.

however, you have to juggle all sorts of factors when you're coming up
with policy decisions for your site...and some of those factors are the
risks vs benefits of any feature or configuration option.

> I do agree though very few typical ISP clients care about this and
> partly as a result of that SMTP e-mail is far less reliable now than
> it used to be in early 90's.

i don't think mail is less reliable now at all. a lot of mail *clients*
are less reliable (not surprising now that microsoft produces internet
software), but mail server software and hardware are both several orders
of magnitude better, faster, and more reliable than they ever were.

you can buy equipment (such as enormous disk arrays and load-balanced
redundant servers) for a virtual pittance these days that no
amount of money could buy in the early 90s. it's just a matter of
planning what you need taking into account expected future growth,
benchmarking/thrash-testing your proposed solutions, and then
implementing what works.

also Linux is, IMO & IME, far more reliable and capable than solaris
ever was...at least it is if you're talking about Debian GNU/Linux.

> Data preservation is a good thing to shoot for.  I don't mean to
> offend either of you and I think I do understand where you're coming
> from, it just seemed an odd thing to have "me too" kind of agreements
> on.

in my experience, the risk is so low that it's not worth worrying about.
really, i'm more worried that my server room is going to catch fire
(or be hit by an asteroid) than i am worried about not fsyncing on the
directories...and i'm not worried by those at all.

in any kind of catastrophe that would cause damage, the practical
difference that fsyncing the directories makes is negligible.

if something like FreeBSD's soft-updates was available for linux
filesystems, then i'd certainly use it (at least if it was available on
reiserfs or xfs)...but i'm not going to lose any sleep over the lack of


craig sanders <cas@taz.net.au>

Fabricati Diem, PVNC.
 -- motto of the Ankh-Morpork City Watch

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