[Gluster-users] Recommended underlining disk storage environment

Stas Oskin
Wed, 03 Dec 2008 12:00:09 -0000

Hi.

Thanks for your detailed answers. I'd like to clarify several points:

2008/12/3 Keith Freedman <freedman at freeformit.com>

> I'm not sure there's an official recommendation.
> I use XFS with much success.
>

Is XFS suitable for massive writing / occasional reading?


>
> I think the choice of underlying filesystem depends highly on the types of
> data you'll be storing and how you'll be storing the info.
> If it's primarily read data, then a filesystem with journaling
capabilities
> may not provide much benefit.  If you'll have lots of files in few
> directories then a filesystem with better large directory metrix would be
> ideal, etc...  Gluster depends on the underlying filesystem, and will work
> no matter what that filesystem is provided it supports extended attributes.
>

I'm going to store mostly large files (100+ MB), with massive writing, and
only occasional read operations.


>
> I've found XFS works great for most purposes.  If you're on
Solaris, I'd
> recommend ZFS.  but It seems people are fond of ReiserFS, but you could
> certainly use EXT3 with extended attributes enabled and be just fine most
> likely.
>

I'm actually prefer to stay on Linux. How well XFS compares to EXT3 in the
environment that I described?


>
> as for LVM.  again, this really depends what you want to do with the data.
> If you need to use multiple physical devices/partitions to present just one
> to gluster you can do that and use LVM to manage your resizing of the
single
> logical volume.


This was the first idea I though about, as I'm going to use 4 disks per
server.

>
> Alternatively, you could use gluster's Unify translator to present one
> effective large/consolidated volume which can be made up of multiple
> devices/partitions.
>

I think I read somewhere in this mailing list that there is a migration from
Unity to DHT in GlusterFS (whichever it means) in the coming 1.4. If Unity
is the legacy approach, what is the relevant solution for 1.4 (DHT)?


>
> In this scenario, you could potentially have multiple underlying
> configurations. You could Unify xfs, reiser, and ext3 filesystems into one
> gluster filesystem.
>
> as for RAID, again, the faster and more appropriately configured the
> underlying system for your data requirements, the better off you will be.
>  If you're going to use gluster's AFR translator, then I'd not
bother with
> hardware raid/mirroring and just use RAID0 stripes, however, if you have
the
> money, and can afford to do RAID0+1, that's always a huge benefit on
read
> performance.  Of course, if you're in a high write environment, then
there's
> no real added value so it's not worth doing.
>

Couple of points here:
1) Thanks to AFR, I actually don't need any fault-tolerant raid (like
mirror), so it's only recommeded in high-volume read enviroments, which is
not the case here. Is this correct?

2) Isn't LVM (or GlusterFS own solution) much better then RAID 0 in sense
that if one of the disks go, the volume still continues to work? This
contrary to RAID where the whole volume goes down?

3) Continuing 2, I think I actually meant JBOD - where you just connect all
the drives and make them look as a single device, rather then stripping.

If you could clarfy the recommended approach, it would be great.


>
> this doesn't realy answer your question, but hopefully it helps.
>
>
>
Thanks again for your help.

Regards.
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