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Re[2]: vim file write mode on journaling fs.

To: linux-xfs@xxxxxxxxxxx
Subject: Re[2]: vim file write mode on journaling fs.
From: Keith Matthews <keith_m@xxxxxxxxxxxxxxxxxxx>
Date: Sun, 12 Aug 2001 13:42:52 +0100 (BST)
In-reply-to: <200108121049.f7CAnxP01518@xxxxxxxxxxxxx>
References: <200108121049.f7CAnxP01518@xxxxxxxxxxxxx>
Sender: owner-linux-xfs@xxxxxxxxxxx
On Sun, 12 Aug 2001 12:49:59 +0200 Bram Moolenaar <Bram Moolenaar 
<Bram@xxxxxxxxxxxxx>> wrote:

> The "pulling the plug" test is a very good way to check what would happen if
> the power fails unexpectedly.  E.g., when a fuse blows.

> >   5. The delayed write you talk about is the norm for ALL filesystems
> >      operating on spinning disks. If you don't delay writes in a filesystem
> >      then you will be here until Christmas responding to this email.
> >      Now XFS has delayed allocation which is different.

> More technical reasons, which explain why it works this way, but give no
> reason to want it that way.

If you feel this way then I suggest you stay with MSDOS which always
uses synchronous writes and suffers performance accordingly.

Every multi-user system I've ever come across works the way you are
objecting to - they have to to get adequate performance, and it does
not matter whether the wait 100 seconds or 10 mSec - there is still a
chance of failure between the OS saying 'OK, I've done' and the data
actually being written to disc. 

The only practical way to achieve what you want in a multi-user OS is
to use transaction mechanisms as used in database systems, and that
would require a redesign of all relevant applications because they
would have to pass 'start of transaction' and 'end of transaction'
messages to the OS.

Keith Matthews                  Spam trap - my real account at this 
                                                        node is keith_m
Frequentous Consultants  - Linux Services, 
                Oracle development & database administration

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