[TriLUG] Using Btrfs

[Paul Boyle]

Hi,

I would like to know the advantages/disadvantages of using btrfs on
Linux machines which are primarily used as scientific workstations.
The workstations typically have staff or student user accounts which
are used for X-ray crystallographic calculations (i.e. floating point
intensive).  The workstations typically contain a single hard drive
(about 500-750GB in size) and an external USB drive to store backups
and almost all workstations can interchange data via NFS.

I've been doing some reading on btrfs (mostly because the Linux distro
I use has made btrfs the default filesystem for its newly released
current version).  In addition, it sounds like the ext4 filesystem is
probably the end of the line for the development of ext series of
filesystems.

I can see a number of advantages of using btrfs which are outlined,
among other places, in this article:

https://www.linux.com/learn/tutorials/533112-weekend-project-get-to-know-btrfs

I guess my main concern is with the default RAID configuration is
regarding how much of my disk gets dedicated to redundant data and
metadata?  Will I need to go and buy second hard drives for all of my
workstations?  I hope these questions don't sound too naive for the IT
professionals who inhabit this list.  My overall goal: I would like
to maximize usable disk space without risking losing data (e.g. I am
considering keeping the metadeta redundant, but not the data).  

How much room do snapshots take up?
  
Can the filesystem be configured to store a certain number (or amount
of data in) snapshots?  If so, how does one determine what is a
reasonable value?

I would appreciate people sharing their experience of any advantages or
pitfalls they have experiences in using btrfs.  (In particular, if you
use btrfs on individual workstations).

If btrfs does seem to be a viable option for me, I would consider
migrating my existing systems to btrfs rather than keeping my my
current multi-partition ext4 formatted hard drives.

Thanks for any input, advice, guidance, etc.

Paul
 

-- 
Paul D. Boyle, Ph. D.
Manager, X-ray Facility
Department of Chemistry
Western University
London, ON N6A 5B7
Canada
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