* Xen pv_ops dom0 2.6.32.13 issues
@ 2010-06-09 21:02 greno
2010-06-09 22:37 ` Jeremy Fitzhardinge
2010-06-09 23:27 ` greno
0 siblings, 2 replies; 11+ messages in thread
From: greno @ 2010-06-09 21:02 UTC (permalink / raw)
To: greno; +Cc: xen-devel
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Xen pv_ops dom0 2.6.32.13 issues
2010-06-09 21:02 Xen pv_ops dom0 2.6.32.13 issues greno
@ 2010-06-09 22:37 ` Jeremy Fitzhardinge
2010-06-09 23:27 ` greno
1 sibling, 0 replies; 11+ messages in thread
From: Jeremy Fitzhardinge @ 2010-06-09 22:37 UTC (permalink / raw)
To: greno; +Cc: xen-devel
On 06/09/2010 02:02 PM, greno@verizon.net wrote:
>
> Ok, I've been running this 2.6.32.13 pv_ops dom0 kernel for several
> weeks and it has twice killed my domU's. I get numerous CPU soft
> lockup bug errors and at times it will freeze which means a power
> cycle boot.
The lockups are in dom0 or domU? Do the backtraces indicate a common
subsystem, or are they all over the place?
> This has resulted in things like:
> EXT-fs error (device dm-0): ext4_lookup: deleted inode reference
> EXT-fs error (device dm-0): ext4_lookup: deleted inode reference
> in the domU boots which has killed two of them.
What's your storage path from guest device to media? Are they using
barriers?
J
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Re: Xen pv_ops dom0 2.6.32.13 issues
@ 2010-06-09 23:27 ` greno
2010-06-09 23:37 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 11+ messages in thread
From: greno @ 2010-06-09 23:27 UTC (permalink / raw)
To: jeremy; +Cc: xen-devel
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xenstore_scan: /local/domain/0/backend/blkbackd
quit on signal: 15
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Xen pv_ops dom0 2.6.32.13 issues
2010-06-09 23:27 ` greno
@ 2010-06-09 23:37 ` Jeremy Fitzhardinge
2010-06-11 17:06 ` Which disk backend to use in domU? Neobiker
0 siblings, 1 reply; 11+ messages in thread
From: Jeremy Fitzhardinge @ 2010-06-09 23:37 UTC (permalink / raw)
To: greno; +Cc: xen-devel
On 06/09/2010 04:27 PM, greno@verizon.net wrote:
> blkbackd
Using phy: in your config file? That really isn't recommended because
it has poor integrity; the writes are buffered in dom0 so writes can be
reordered or lost on crash, and the guest filesystem can't maintain any
of its own integrity guarantees.
tap:aio: is more resilient, since the writes go directly to the device
without buffering.
That doesn't directly relate to your lockup issues, but it should
prevent filesystem corruption when they happen.
J
>
>
>
> Jun 9, 2010 07:13:23 PM, jeremy@goop.org wrote:
>
> On 06/09/2010 04:05 PM, greno@verizon.net wrote:
> > Jeremy,
> > The soft lockups seemed to be occurring in different systems. And I
> > could never make sense out of what was triggering them. I have not
> > mounted any file systems with "nobarriers" in guests. The guests are
> > all a single /dev/xvda. The underlying physical hardware is LVM over
> > RAID-1 arrays. I'm attaching dmesg, kern.log, and messages in case
> > these might be useful.
>
> Using what storage backend? blkback? blktap2?
>
> J
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Which disk backend to use in domU?
2010-06-09 23:37 ` Jeremy Fitzhardinge
@ 2010-06-11 17:06 ` Neobiker
2010-06-11 17:42 ` Valtteri Kiviniemi
0 siblings, 1 reply; 11+ messages in thread
From: Neobiker @ 2010-06-11 17:06 UTC (permalink / raw)
To: xen-devel
Hello Jeremy,
Jeremy Fitzhardinge wrote:
> Using phy: in your config file? That really isn't recommended because it
> has poor integrity; the writes are buffered in dom0 so writes can be
> reordered or lost on crash, and the guest filesystem can't maintain any
> of its own integrity guarantees.
>
> tap:aio: is more resilient, since the writes go directly to the device
> without buffering.
Do you mean that using tap:aio with a disk.image is prefered against using
phy: with LVM-device?
Best Regards
Jens Friedrich aka Neobiker (www.neobiker.de)
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-11 17:06 ` Which disk backend to use in domU? Neobiker
@ 2010-06-11 17:42 ` Valtteri Kiviniemi
2010-06-11 17:53 ` Valtteri Kiviniemi
0 siblings, 1 reply; 11+ messages in thread
From: Valtteri Kiviniemi @ 2010-06-11 17:42 UTC (permalink / raw)
Cc: xen-devel
Hi,
I am also using phy: with LVM-partitions, and I also would like to know
if there is a better or more preferred way.
- Valtteri Kiviniemi
Neobiker kirjoitti:
> Hello Jeremy,
>
>
> Jeremy Fitzhardinge wrote:
>> Using phy: in your config file? That really isn't recommended because it
>> has poor integrity; the writes are buffered in dom0 so writes can be
>> reordered or lost on crash, and the guest filesystem can't maintain any
>> of its own integrity guarantees.
>>
>> tap:aio: is more resilient, since the writes go directly to the device
>> without buffering.
>
> Do you mean that using tap:aio with a disk.image is prefered against using
> phy: with LVM-device?
>
> Best Regards
> Jens Friedrich aka Neobiker (www.neobiker.de)
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-11 17:42 ` Valtteri Kiviniemi
@ 2010-06-11 17:53 ` Valtteri Kiviniemi
2010-06-11 18:11 ` Neobiker
0 siblings, 1 reply; 11+ messages in thread
From: Valtteri Kiviniemi @ 2010-06-11 17:53 UTC (permalink / raw)
To: xen-devel
Hi,
Ah, misunderstanding sorry, you were talking about disk images :)
Valtteri Kiviniemi kirjoitti:
> Hi,
>
> I am also using phy: with LVM-partitions, and I also would like to know
> if there is a better or more preferred way.
>
> - Valtteri Kiviniemi
>
> Neobiker kirjoitti:
>> Hello Jeremy,
>>
>>
>> Jeremy Fitzhardinge wrote:
>>> Using phy: in your config file? That really isn't recommended
>>> because it
>>> has poor integrity; the writes are buffered in dom0 so writes can be
>>> reordered or lost on crash, and the guest filesystem can't maintain any
>>> of its own integrity guarantees.
>>>
>>> tap:aio: is more resilient, since the writes go directly to the device
>>> without buffering.
>>
>> Do you mean that using tap:aio with a disk.image is prefered against
>> using
>> phy: with LVM-device?
>>
>> Best Regards
>> Jens Friedrich aka Neobiker (www.neobiker.de)
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-11 17:53 ` Valtteri Kiviniemi
@ 2010-06-11 18:11 ` Neobiker
2010-06-14 10:49 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 11+ messages in thread
From: Neobiker @ 2010-06-11 18:11 UTC (permalink / raw)
To: xen-devel
Hi
Valtteri Kiviniemi-2 wrote:
>
> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
>
I'm talking about this config:
disk = [
'phy:/dev/vm/vm01,xvda1,w',
'phy:/dev/vm/vm01-swap,xvda2,w',
'phy:/dev/daten/devel_debian_amd64,xvda3,w',
]
BR neobiker
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-11 18:11 ` Neobiker
@ 2010-06-14 10:49 ` Jeremy Fitzhardinge
2010-06-14 10:57 ` Daniel Stodden
2010-06-14 11:01 ` Pasi Kärkkäinen
0 siblings, 2 replies; 11+ messages in thread
From: Jeremy Fitzhardinge @ 2010-06-14 10:49 UTC (permalink / raw)
To: Neobiker; +Cc: xen-devel, Daniel Stodden
On 06/11/2010 07:11 PM, Neobiker wrote:
> Hi
>
> Valtteri Kiviniemi-2 wrote:
>
>> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
>>
>>
> I'm talking about this config:
> disk = [
> 'phy:/dev/vm/vm01,xvda1,w',
> 'phy:/dev/vm/vm01-swap,xvda2,w',
> 'phy:/dev/daten/devel_debian_amd64,xvda3,w',
> ]
>
file: is definitely unsafe; its IO gets buffered in the dom0 pagecache,
which means the guests writes aren't really writes. I believe phy: has
similar problems, whereas tap:aio: implemented direct IO. But someone
more storagey can confirm.
J
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-14 10:49 ` Jeremy Fitzhardinge
@ 2010-06-14 10:57 ` Daniel Stodden
2010-06-14 11:01 ` Pasi Kärkkäinen
1 sibling, 0 replies; 11+ messages in thread
From: Daniel Stodden @ 2010-06-14 10:57 UTC (permalink / raw)
To: Jeremy Fitzhardinge; +Cc: Neobiker, xen-devel
On Mon, 2010-06-14 at 06:49 -0400, Jeremy Fitzhardinge wrote:
> On 06/11/2010 07:11 PM, Neobiker wrote:
> > Hi
> >
> > Valtteri Kiviniemi-2 wrote:
> >
> >> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
> >>
> >>
> > I'm talking about this config:
> > disk = [
> > 'phy:/dev/vm/vm01,xvda1,w',
> > 'phy:/dev/vm/vm01-swap,xvda2,w',
> > 'phy:/dev/daten/devel_debian_amd64,xvda3,w',
> > ]
> >
>
> file: is definitely unsafe; its IO gets buffered in the dom0 pagecache,
> which means the guests writes aren't really writes. I believe phy: has
> similar problems, whereas tap:aio: implemented direct IO. But someone
> more storagey can confirm.
Unless there's a difference in type names between XCP and .org, 'phy'
means a bare LUN plugged into blkback?
Those run underneath the entire block cache subsystems, which ironically
has caching issues of it's own.
But your writes are safe.
Daniel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: Which disk backend to use in domU?
2010-06-14 10:49 ` Jeremy Fitzhardinge
2010-06-14 10:57 ` Daniel Stodden
@ 2010-06-14 11:01 ` Pasi Kärkkäinen
1 sibling, 0 replies; 11+ messages in thread
From: Pasi Kärkkäinen @ 2010-06-14 11:01 UTC (permalink / raw)
To: Jeremy Fitzhardinge; +Cc: Neobiker, xen-devel, Daniel Stodden
On Mon, Jun 14, 2010 at 11:49:45AM +0100, Jeremy Fitzhardinge wrote:
> On 06/11/2010 07:11 PM, Neobiker wrote:
> > Hi
> >
> > Valtteri Kiviniemi-2 wrote:
> >
> >> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
> >>
> >>
> > I'm talking about this config:
> > disk = [
> > 'phy:/dev/vm/vm01,xvda1,w',
> > 'phy:/dev/vm/vm01-swap,xvda2,w',
> > 'phy:/dev/daten/devel_debian_amd64,xvda3,w',
> > ]
> >
>
> file: is definitely unsafe; its IO gets buffered in the dom0 pagecache,
> which means the guests writes aren't really writes. I believe phy: has
> similar problems, whereas tap:aio: implemented direct IO. But someone
> more storagey can confirm.
>
I though phy: submits direct bio's bypassing dom0 pagecache..
-- Pasi
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2010-06-14 11:01 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-06-09 21:02 Xen pv_ops dom0 2.6.32.13 issues greno
2010-06-09 22:37 ` Jeremy Fitzhardinge
2010-06-09 23:27 ` greno
2010-06-09 23:37 ` Jeremy Fitzhardinge
2010-06-11 17:06 ` Which disk backend to use in domU? Neobiker
2010-06-11 17:42 ` Valtteri Kiviniemi
2010-06-11 17:53 ` Valtteri Kiviniemi
2010-06-11 18:11 ` Neobiker
2010-06-14 10:49 ` Jeremy Fitzhardinge
2010-06-14 10:57 ` Daniel Stodden
2010-06-14 11:01 ` Pasi Kärkkäinen
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