[Gluster-users] Hardware Sizing Requirments

[Whit Blauvelt]

> We will be deploying 2 gluster nodes (relica-mode) across 2 of our sites.
> The sites are connected over 8Gig dark fibre. Our storage disks will be
> assigned from EMC VNX storage (SAS/NL-SAS disks).
> 
> This gluster volume will be mounted on 2 application servers, 1 on each
> site. The application will be load balanced for user access. This volume
> mount-point will act as the data directory for user data. We will have
> about 500 users performing simultaneous read-writes to the volume.
> 
> In this scenario, what would be the recommended memory/CPU requirements
> for the gluster nodes. Each node gluster node will be a virtual machine
> (Centos 6.4 / GlusterFS 3.3.2).

My understanding is that replica mode is designed for local replication, not
replication between sites. There's also geo-replication, but that's a
different animal entirely, a master-slave relationship, not master-master,
so it wouldn't work if your users are distributed across two distant sites.

If this doesn't rule out Gluster for your use-case, that is if all your
users are on one end and it's geo-replication, not replica mode you'll be
using, you'll still need to let us know about typical file sizes, number of
files, and so on. The number of users doesn't tell us much. If it's 500
employees who all might write a Word document at the same time, that's far
different from 500 high-volume websites backed by complex operations on a
LAMP stack.

Also, EMC VNX may not be suitable. Haven't used it, but EMC says you connect
to it by "CIFS, NFS, pNFS, MPFS." Gluster needs to be able to directly deal
with an XFS or EXT4 file system. Gluster then allows mounting that file
system by NFS or GlusterFS, but you can't put Gluster _on_ a file system
mounted by CIFS or NFS. They don't provide the extended attributes Gluster
requires. The underlying storage has to be locally, natively mounted, AFAIK.
Now, you _might_ be able to do something like put an XFS or EXT4 filesystem
within a TrueCrypt file which is in turn on a file system within a remote
mount on the EMC VNX, but your performance will suck.

Best,
Whit