2008-06-17 05:59:32

by Gary Hawco

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Subject: Ordered data mode vs. writeback mode

Noticed that the newest set of patches in ext4-patch-queue has ordered data
mode as the default mode again. Tune2fs is now able to switch modes again.

What is the preferred mode for a home desktop system with ext4? Is
writeback still the fastest, but ordered data has more data integrity? And
does delalloc only work when writeback is enabled? And does the commit=XX
seconds still only work with writeback mode, ala ext3, or is it a valid
option with ordered data mode?

Trying to get an idea of the plethora of new options available with ext4.

Keep up the good work!

Gary





2008-06-17 14:34:11

by Andreas Dilger

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Subject: Re: Ordered data mode vs. writeback mode

On Jun 16, 2008 22:59 +0000, Gary Hawco wrote:
> What is the preferred mode for a home desktop system with ext4? Is
> writeback still the fastest, but ordered data has more data integrity? And
> does delalloc only work when writeback is enabled? And does the commit=XX
> seconds still only work with writeback mode, ala ext3, or is it a valid
> option with ordered data mode?

Using ordered mode is the default and preferred mode.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.


2008-06-17 18:41:46

by Mingming Cao

[permalink] [raw]
Subject: Re: Ordered data mode vs. writeback mode


On Mon, 2008-06-16 at 22:59 +0000, Gary Hawco wrote:
> Noticed that the newest set of patches in ext4-patch-queue has ordered data
> mode as the default mode again. Tune2fs is now able to switch modes again.
>
> What is the preferred mode for a home desktop system with ext4? Is
> writeback still the fastest, but ordered data has more data integrity? And
> does delalloc only work when writeback is enabled?

The update patch queue has patch to support delalloc on new ordered
mode. There seems an issue, Aneesh is debugging it now.

> And does the commit=XX
> seconds still only work with writeback mode, ala ext3, or is it a valid
> option with ordered data mode?
>
Should work for both mode.


Mingming