[clug] Ext2 vs Ext3: weird benchmark result

[Daniel Pittman]

Nathan O'Sullivan <nathan at mammoth.com.au> writes:

>> You can't remount as ext3 without unmounting, which for the rootfs is not
>> trivially possible, so this is "if it was ext3 or ext2" and all.
>
> $ cat /proc/cmdline
> root=/dev/xvda2 rootfstype=ext2 ro clocksource=tsc
>
> $ dmesg | grep -i ext[23]
> Kernel command line: root=/dev/xvda2 rootfstype=ext2 ro clocksource=tsc
> EXT2-fs warning (device xvda2): ext2_fill_super: mounting ext3 filesystem as
> ext2
> VFS: Mounted root (ext2 filesystem) readonly on device 202:2.
>
> $ grep ext /etc/fstab
> /dev/xvda2 / ext3 noatime,nodiratime,errors=remount-ro 0 1
>
> $ mount | grep ext
> /dev/xvda2 on / type ext3 (rw,noatime,nodiratime,errors=remount-ro)
>
> Is the output of 'mount' wrong, or am I just not understanding what you've
> said?

The output of mount is wrong, I expect: that should be showing you the content
of /etc/mtab, which is maintained in user-space by the software.  Check
/proc/mounts, which is the kernel view of the same data, and see what it has
to say.

Also, if it is really mounted as ex3 you should see the kernel ext3 messages
in the kernel message log:

[71789.271868] kjournald starting.  Commit interval 5 seconds
[71789.272296] EXT3 FS on dm-5, internal journal
[71789.272310] EXT3-fs: mounted filesystem with ordered data mode.

I suspect those don't show up anywhere in your guest, right?

        Daniel
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