[Grml] EXT3-fs: barriers not enabled

[Sven Crouse]

Hi GRML. I appreciate your system, have been using since 2008.
Recently learned about persistency which I plan to use to replace custom
initramfs for booting & maintenance of RAID1/LVM2 systems containing
root partitions.

I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. This is 2.6.36
kernel with lvm2 version 2.02.73. I thought to try to grml 2010.12 as
well, but problem remains.

My question: is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ? We can otherwise mount partitions without
incident. Does somebody have ext3 barriers enabled by default such that
I know it should be realized with 2010.12 ?

Appreciatively,

Sven

[Christian Hofstädtler]

Sven,

Post by Sven Crouse
I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. ?In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. ?This is 2.6.36
kernel with lvm2 version 2.02.73. ?I thought to try to grml 2010.12 as
well, but problem remains.

This probably means that the underlying blockdevice does not support
write barriers.
2.6.36 should support write barriers in the md and dm layers, but your
underlying block device still has to support that, too.

Post by Sven Crouse
My question: ?is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ?

No.

You could try running your test with a stock Debian kernel and see if
it works there, just to do a quick verification.


Cheers,
Christian

[Sven Crouse]

Hi GRML. I appreciate your system, have been using since 2008.
Recently learned about persistency which I plan to use to replace custom
initramfs for booting & maintenance of RAID1/LVM2 systems containing
root partitions.

I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. This is 2.6.36
kernel with lvm2 version 2.02.73. I thought to try to grml 2010.12 as
well, but problem remains.

My question: is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ? We can otherwise mount partitions without
incident. Does somebody have ext3 barriers enabled by default such that
I know it should be realized with 2010.12 ?

Appreciatively,

Sven

[Christian Hofstädtler]

Sven,

Post by Sven Crouse
I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. ?In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. ?This is 2.6.36
kernel with lvm2 version 2.02.73. ?I thought to try to grml 2010.12 as
well, but problem remains.

This probably means that the underlying blockdevice does not support
write barriers.
2.6.36 should support write barriers in the md and dm layers, but your
underlying block device still has to support that, too.

Post by Sven Crouse
My question: ?is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ?

No.

You could try running your test with a stock Debian kernel and see if
it works there, just to do a quick verification.


Cheers,
Christian

[Sven Crouse]

Hi GRML. I appreciate your system, have been using since 2008.
Recently learned about persistency which I plan to use to replace custom
initramfs for booting & maintenance of RAID1/LVM2 systems containing
root partitions.

I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. This is 2.6.36
kernel with lvm2 version 2.02.73. I thought to try to grml 2010.12 as
well, but problem remains.

My question: is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ? We can otherwise mount partitions without
incident. Does somebody have ext3 barriers enabled by default such that
I know it should be realized with 2010.12 ?

Appreciatively,

Sven

[Christian Hofstädtler]

Sven,

Post by Sven Crouse
I just finished migrating Gentoo from single partition to mirrored
( RAID1 ) and LVM2 volumes. ?In the process, I learned/realized that the
Ext3 filesystems contained within raid/volume group are not enabling
write barriers despite being told by fstab to do so. ?This is 2.6.36
kernel with lvm2 version 2.02.73. ?I thought to try to grml 2010.12 as
well, but problem remains.

This probably means that the underlying blockdevice does not support
write barriers.
2.6.36 should support write barriers in the md and dm layers, but your
underlying block device still has to support that, too.

Post by Sven Crouse
My question: ?is there any magic "Start" besides mdadm-raid, lvm that
should be necessary ?

No.

You could try running your test with a stock Debian kernel and see if
it works there, just to do a quick verification.


Cheers,
Christian