Re: Set nodatacow per file?

From: Chester <somethingsome2000@gmail.com>
To: dima <dolenin@parallels.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Set nodatacow per file?
Date: Mon, 27 Feb 2012 16:10:50 -0600	[thread overview]
Message-ID: <CAAE6i0hmL5ZRaGYhWptt4qDvKz1SF=6L=Q_MF4Uow5txavTa1g@mail.gmail.com> (raw)
In-Reply-To: <4F4B8B02.9080303@parallels.com>

On Mon, Feb 27, 2012 at 7:54 AM, dima <dolenin@parallels.com> wrote:
> Hello,
>
> Since several people asked to post the results, here they are.
> I tried raw virtio disk with and without -z -C set and also qcow2 vir=
tio
> disk without -z -C set and did not notice any difference in performan=
ce at
> all - Redhat 6.2 Minimal installs in 10 minutes in each case. The "ab=
ysmal"
> performance as it was some several months ago (like 10 minutes just f=
or
> virtual disk formatting) under the same conditions is no more at leas=
t on
> 3.3.0-rc5.

Just to make sure, this is a _new_ virtual disk right? I can barely
contain my excitement right now. This is amazing progress.

>
> best
> ~dima
>
>
>
> On 02/24/2012 02:22 PM, dima wrote:
>>
>> On 02/13/2012 04:17 PM, Ralf-Peter Rohbeck wrote:
>>>
>>> Hello,
>>> is it possible to set nodatacow on a per-file basis? I couldn't fin=
d
>>> anything.
>>> If not, wouldn't that be a great feature to get around the performa=
nce
>>> issues with VM and database storage? Of course cloning should still
>>> cause COW.
>>
>>
>> Hello,
>> Going back to the original question from Ralf I wanted to share my
>> experience.
>>
>> Yesterday I set up KVM+qemu and set -z -C with David's 'fileflags'
>> utility for the VM image file.
>> I was very pleased with results - Redhat 6 Minimal installation was
>> installed in 10 minutes whereas it was taking 'forever' the last tim=
e I
>> tried it some 4 months ago. Writes during installation were very
>> moderate. Performance of VM is excellent. Installing some big packag=
es
>> with yum inside VM goes very quickly with the speed indistinguishabl=
e
>> from that of bare metal installs.
>>
>> I am not quite sure should this improvement be attributed to the noc=
ow
>> and nocompress flags or to the overall improvement of btrfs (I am on
>> 3.3-rc4 kernel) but KVM is definitely more than usable on btrfs now.
>>
>> I am yet to test the install speed and performance without those fla=
gs
>> set.
>>
>> best
>> ~dima
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrf=
s" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs=
" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html