[CentOS] Convert Filesystem to Ext4

Tue Apr 19 19:32:06 UTC 2011
Brandon Ooi <brandono at gmail.com>

On Apr 19, 2011, at 11:55 AM, Ryan Wagoner <rswagoner at gmail.com> wrote:

> On Tue, Apr 19, 2011 at 2:29 PM, Scott Silva <ssilva at sgvwater.com> wrote:
>> on 4/19/2011 11:16 AM Scott Silva spake the following:
>>> on 4/19/2011 10:42 AM Matt spake the following:
>>>> On a running 64 bit CentOS 5.6 box is it possible to convert from Ext3
>>>> to Ext4 to improve performance?  Right now I can deal with a few hours
>>>> of downtime on it.  This is an email server with lots of I/O due to
>>>> seek time.  Software RAID1 as well.  Will Ext4 offer much of an
>>>> improvement?
>>> http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/96/html/Migration_Planning_Guide/ch03s02.html
>> I know it is for RH 6, but probably sound advice.
> I converted my file server to ext4. The conversion went smoothly, but
> I highly recommend making a backup. You need to first turn on the ext4
> features then run fsck to finish the process. The conversion takes as
> long as a fsck takes on ext3.
> tune4fs -O extents,uninit_bg,dir_index /dev/
> e4fsck -yfDC0 /dev/
> Ryan
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Mail servers with high I/O won't get much (if any) of a performance boost. It's an i/o issue not something that ext4 can help you with except possibly a faster fsck if things go down. Things like delayed allocation.. extents.. Don't help with millions of tiny files. 

Faster drives and hardware raid with write cache. Better if you can have multiple disk sets and spread i/o around.