[Gluster-users] Hardware Sizing Requirments

[Bobby Jacob]

HI,

Both the gluster nodes are virtual machines. We have EMC storage available on both the sites. The LUN's from EMC storage is presented to both these nodes. I was thinking, we present LUN's from either storage to the gluster nodes present on either sites. These LUN's will be then mounted on the gluster nodes (bricks) using xfs filesystem. Then I create a gluster volume using them and mount that volume on the application servers (2) that's present on either site. Both these sites are connected using a dedicated 2GBps dark fibre.

What we are looking for with this setup is to implement a dropbox like concept for users. Each user will be 1GB quota available to them. This is being done by the application itself. The only restriction we plan to impose is to restrict the maximum size of the file that the user can upload. 

Thanks & Regards,
Bobby Jacob

-----Original Message-----
From: Whit Blauvelt [mailto:whit.gluster at transpect.com] 
Sent: Thursday, August 29, 2013 4:25 PM
To: Bobby Jacob
Cc: gluster-users at gluster.org
Subject: Re: [Gluster-users] Hardware Sizing Requirments

> 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