Re: [MooseFS-Users] Min goal to prevent data loss

[David M. <dav...@pr...>]

Thanks Piotr and Wolfgang.

I have interpreted the term "copy" incorrectly. I thought a copy was an additional instance of the file, so a goal of 2 would result in the file plus 2 copies of it, thus 3 instances of the file.

I also thought this because it explained the size of my mfs mount - I have rsync'd ~500GB of data into my mfs mount, and the CGI stats show ~1.5TB of disk used at a goal of 2. Based off this I assumed each file had 3 instances. What would account for 1.5TB of storage usage if 500GB of files only exist twice at a goal of 2?

Thanks,
Dave

-------- Original Message --------
Subject: Re: [MooseFS-Users] Min goal to prevent data loss
Local Time: May 12, 2017 10:31 AM
UTC Time: May 12, 2017 2:31 PM
From: pio...@mo...
To: David Myer <dav...@pr...>
moo...@li... <moo...@li...>

Hi David,

> Wouldn't a file exist in 2 places if the goal was 1?

No. If file had goal = 1, it had only one copy.

Goal means number of copies, so the best practice is to set the goal to 2 minimum for whole filesystem, e.g.:
mfssetgoal -r 2 /mnt/mfs

MooseFS will then automatically take care of replication of files to other servers to fulfil the goal.

Best regards,
Peter

--
Piotr Robert Konopelko
MooseFS Client Support Team | moosefs.com

> On 12 May 2017, at 3:54 PM, David Myer <dav...@pr...> wrote:
>
> Hi,
>
> The MooseFS best practices recommend a min goal of 2 to prevent eventual data loss. Wouldn't a file exist in 2 places if the goal was 1?
>
> Thanks,
> Dave
>
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