[Lustre-discuss] Storage management question

[Andy Pace]

How would I go about moving that file to another OST and letting the MDS know of the new location?

-----Original Message-----
From: lustre-discuss-bounces at lists.lustre.org [mailto:lustre-discuss-bounces at lists.lustre.org] On Behalf Of Andreas Dilger
Sent: Wednesday, June 02, 2010 3:03 PM
To: Andy Pace
Cc: lustre-discuss at lists.lustre.org
Subject: Re: [Lustre-discuss] Storage management question

On 2010-06-02, at 12:04, Andy Pace wrote:
> but what I'm wondering is how the metadata handles the move (if at all) of data if one of the OSS's runs out of data.
>  
> Here's a scenario:
>  
> Instance #1 -> MDS sends to OSS1
> Instance #2 -> MDS sends to OSS2
> Instance #3 -> MDS sends to OSS1

s/OSS/OST/

The OSS is the server node, the OST is the storage.

> Suddenly both instance #1 and #3 consume all available storage on OSS1. What happens then? Does the MDS send any further writes to OSS2? As far as I know there is no way to move around data using the MDS to a different OSS, so I'm a bit confused. Striping may slow this specific scenario down, but the lack of resiliency is something we're still testing - dabbling with DRBD.

If you are writing new files, they will be load balanced before OST2 completely fills up.  If you are writing to the same file (i.e. a huge single image file) then the writers to OST1 will get ENOSPC.


Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.

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