Gluster users - Jun 2012 - Striped replicated volumes in Gluster 3.3.0

Hi all,
I'm very happy to see the release of 3.3.0. One of the features I was
waiting for are striped replicated volumes. We plan to store KVM
images (from a OpenStack installation) on it.
I read through the docs and found the following phrase: "In this
release, configuration of this volume type is supported only for Map
Reduce workloads."
What does that mean exactly? Hopefully not, that I'm unable to store
my KVM images on it?

Cheers,
Christian

Did an answer to Christian's question pop up?  I was going to write in with
the exact same one.

If I created a replicated striped volume, what would keep it from working
in a non-Hadoop environment?  Does the NFS server refuse to export such a
volume?  Does the FUSE client refuse to mount such a volume?

Thanks,

 - Travis

On Fri, Jun 1, 2012 at 2:37 AM, <gluster-users-request at gluster.org>
wrote:
> ---------- Forwarded message ----------
> From: Christian Wittwer <wittwerch at gmail.com>
> To: Gluster-users at gluster.org
> Cc:
> Date: Fri, 1 Jun 2012 08:00:27 +0200
> Subject: [Gluster-users] Striped replicated volumes in Gluster 3.3.0
> Hi all,
> I'm very happy to see the release of 3.3.0. One of the features I was
> waiting for are striped replicated volumes. We plan to store KVM
> images (from a OpenStack installation) on it.
> I read through the docs and found the following phrase: "In this
> release, configuration of this volume type is supported only for Map
> Reduce workloads."
> What does that mean exactly? Hopefully not, that I'm unable to store
> my KVM images on it?
>
> Cheers,
> Christian
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://supercolony.gluster.org/pipermail/gluster-users/attachments/20120601/33e0ccc6/attachment.html>

On 06/04/2012 11:21 AM, Amar Tumballi wrote:
> On 06/01/2012 10:18 PM, Travis Rhoden wrote:
>> Did an answer to Christian's question pop up? I was going to write
in
>> with the exact same one.
>>
>> If I created a replicated striped volume, what would keep it from
>> working in a non-Hadoop environment? Does the NFS server refuse to
>> export such a volume? Does the FUSE client refuse to mount such a
volume?
>>
>> I read through the docs and found the following phrase: "In this
>> release, configuration of this volume type is supported only for Map
>> Reduce workloads."
>> What does that mean exactly? Hopefully not, that I'm unable to
store
>> my KVM images on it?
>>
>>
>
Hi,

Striped-Replicated Volumes can be created like any other volume type
with GlusterFS-3.3.0. It is not restricted to be exported with NFS or
FUSE. It would still work with non-Hadoop environment.

The statement is the documentation is because of what we tested the type
of volume with. Considering the other type of volumes, Striped-Replicate
volume has been tested only with Hadoop workload as of now.

You can use striped-replicate volume, but have a test run for some time
before putting into production. If it works for you, we can say that
feature is good, but if there are issues, we are glad to fix it and make
it more stable.

Regards,
Amar

It is essential to see the ratio of: No of active VMs / No of servers. If
it is >= 1 (which is usually the case) then you already aren't getting
the
theoretical claims of striping (apart from the configuration overheads and
complexity).

Avati

On Tue, Jun 5, 2012 at 8:58 AM, Fernando Frediani (Qube) <
fernando.frediani at qubenet.net> wrote:
>  I think the main limitation of using other than strip+repl type is that
> first the maximum size of a file is the size of a brick and sometimes
> Virtual Machines tend to be really big, second is that the performance of a
> single image file (say .VMDK for example) will be limited to a a
single's
> brick performance, while if you could strip that big file accross multiple
> nodes it would spread the IOPS as well through several RAID controllers and
> caching systems.
> But I've tried that type of volume and it didn't work at all to run
> Virtual Machines.
>
> Fernando
>
>  ------------------------------
> *From:* gluster-users-bounces at gluster.org [
> gluster-users-bounces at gluster.org] on behalf of Anand Avati [
> anand.avati at gmail.com]
> *Sent:* 05 June 2012 16:41
> *To:* Whit Blauvelt
> *Cc:* gluster-users at gluster.org
>
> *Subject:* Re: [Gluster-users] Striped replicated volumes in Gluster 3.3.0
>
>
>
> On Tue, Jun 5, 2012 at 8:29 AM, Whit Blauvelt <whit.gluster at
transpect.com>wrote:
>
>> On Tue, Jun 05, 2012 at 08:13:37AM -0700, Anand Avati wrote:
>>
>> > Whit,
>> >  There has been no drop in goal. There are many parts to
"supporting a
>> VM
>> > workload". The goals listed for 3.3 are definitely met - to
make VMs
>> work good
>> > enough (fix self-heal locking issues, some FUSE upstream work for
>> supporting
>> > O_DIRECT etc.) However, for 3.4 we have bigger goals of supporting
VM
>> image use
>> > case in a much better way - libglusterfsclient integration for
QEMU
>> etc. This
>> > was what Amar was referring to. I hope I clarified your doubt, and
>> apologies
>> > for the confusion.
>>
>>  Thanks for the clarification, Avanti. So if "VMs work good
enough" now,
>> the
>> recommendation is that in general Gluster is ready for production work
>> with
>> VMs? Performance should be acceptable, if not always spectacular? Or
>> should
>> VM use be considered more in the beta area still, until 3.3.1 or
whatever?
>>
>> I know there's no substitute for testing it in a particular
environment.
>> Just trying to get the general overview before committing to that.
>>
>>
>  You are definitely expected and encouraged to test out VMs in a test
> environment. This is the first public release with the announced VM support
> and there is only so much what internal QA can cover. While there are no
> known issues, we are actively awaiting feedback from all your beta testing.
> About performance - FUSE is something which will be a fundamental limit to
> how much performance you get expect for a VM image. Whether that is good
> enough for you or not is something only you can decide. We have heard many
> users say they are very satisfied. Some might not be. The
> libglusterfsclient based QEMU integration is for this very purpose of
> avoiding context switches you get with a FUSE filesystem. That would
> however be an add-on, and FUSE mount based VM image will still work.
>
>  Avati
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://supercolony.gluster.org/pipermail/gluster-users/attachments/20120605/c782958c/attachment.html>