[Lustre-devel] Control file striping

Kalyana C ckkccf at gmail.com
Mon Nov 5 10:01:10 PST 2012


> Have you considered using a combination of OST Pools and striping
fit your needs?

This is the only way possible that I currently know of.

But is it possible to manage OST pools via an API call? Can it be done from
a client under a normal user application? Or does it have the same
restrictions as described at
http://wiki.lustre.org/index.php/Creating_and_Managing_OST_Pools

Regards,
Kalyan

On Mon, Nov 5, 2012 at 11:57 AM, Ben Evans <Ben.Evans at terascala.com> wrote:

> Have you considered using a combination of OST Pools and striping fit
> your needs?
>
> -----Original Message-----
> From: lustre-devel-bounces at lists.lustre.org
> [mailto:lustre-devel-bounces at lists.lustre.org] On Behalf Of Atchley,
> Scott
> Sent: Monday, November 05, 2012 12:47 PM
> To: Kalyana C
> Cc: lustre-devel at lists.lustre.org
> Subject: Re: [Lustre-devel] Control file striping
>
> On Nov 3, 2012, at 1:41 PM, Kalyana C <ckkccf at gmail.com> wrote:
>
> > Hello,
> >
> > I am trying to figure out a way to:
> >
> > set striping across a set of OSTs of my choice.
> >
> > lfs setstripe command and API call does not allow for this currently.
> The user can only set the starting OST through the index parameter. I
> appreciate why there is no such feature currently; you do not want to
> let the users have control on how OSTs are used since it can result in
> OST usage imbalance.
> >
> > However, I do have a valid usage case for such a feature and I am
> trying to figure out the best way to do it.
>
> I have a valid use for it as well. It would be nice to have this feature
> back.
>
> Scott
>
> >
> > One way to achieve the same result is through the use of OST pools.
> However, the userland tools do not work from a client node, it has to be
> run on the MGS. There are also other restrictions as described here:
> http://wiki.lustre.org/index.php/Creating_and_Managing_OST_Pools
> >
> > I am also digging through the Lustre source and header files to see if
> there are other (undocumented) ways to do this.
> >
> > So, my questions are as follows:
> >
> > 1) Is there currently a way for a user to control the striping of a
> file / directory on a selected set of OSTs? If yes, is it possible to do
> it through an API call or a command line utility?
> >
> > 2) If answer to (1) is No, Is there a way to do this with admin rights
> from the MDS or client nodes?
> >
> > 3) If pools are the only way to achieve this, is there an API call to
> create, manage and destroy pools from a user application? Is there any
> impact on performance of MDS components if pools are dynamically created
> and deleted on demand? Can the API be called from a client node (root or
> user) or does it have to be on the MGS?
> >
> > Thank you.
> >
> > Regards,
> > Kalyana Chadalavada
> >
> > _______________________________________________
> > Lustre-devel mailing list
> > Lustre-devel at lists.lustre.org
> > http://lists.lustre.org/mailman/listinfo/lustre-devel
>
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