Re: [Moosefs-users] Backing up MFS metadata

[Michał B. <mic...@ge...>]

Hi!

 

Master server flushes metadata kept in RAM to the metadata.mfs.back binary
file every hour on the hour (xx:00). So probably the best moment would be to
copy the metadata file every hour on the half hour (30 minutes after the
dump). Then you would maximally lose 1.5h of data. You can choose any method
of copying - cp, scp, rsync, etc. Metalogger receives the metadata file
every 24 hours so it is better to copy metadata from the master server.

 

Having metadata backed up you won't see newly created files, files to which
some data was appended would come back to the previous size, there would
still exist deleted files and files you changed names of would come back to
their previous names (and locations). But still you would have information
and access to all the files created in the X past years.

 

If you have not read this entry, we strongly recommend it:

http://www.moosefs.org/news-reader/items/metadata-ins-and-outs.html 

 

 

Kind regards

Michał 

 

 

 

From: Stas Oskin [mailto:sta...@gm...] 
Sent: Tuesday, July 06, 2010 12:07 PM
To: moo...@li...
Subject: [Moosefs-users] Backing up MFS metadata

 

Hi.

Is there any recommended procedure how to back-up MFS meta-data?

I.e: 

* Where to backup from - master or logger?
* Backup the flat files, or use some mfs tool?
* Should I stop the logger before?

Thanks!