[Gluster-users] System Requirements (and mild rant re: lack-of-documentation)

Craig Carl craig at gluster.com
Sun Sep 26 02:38:58 UTC 2010

Jonathan - 
We are actively working on the documentation, we will release an entirely new set with Gluster 3.1, currently in beta. In the mean time you can find the system requirements here - 
http://www.gluster.com/community/documentation/index.php/Storage_Server_Installation_and_Configuration#Technical_Requirements . 

I'd also suggest the Introduction to Gluster document - 
We also have a Gluster Architecture document - 

Gluster has standardized on some language recently, a 'node' or a 'brick' is a single host with block storage that Gluster will add to a cluster and export via a NAS protocol. We call it a 'storage server'. 

You will need some number of 'storage servers' to meet your performance requirements. The general guidelines for determining the performance of a single storage server are; 

1. For files > 64KB Gluster will run at hardware speeds. 
2. In 90% of Gluster environments the hardware limitation is network I/O. 
3. For files <64KB CPU speeds become more relevant and performance may be reduced to ~60% of hardware performance due to context switching. This is a general NAS issue, not specifically a Gluster problem. 
4. If you use the GlusterFS client and setup a mirror write performance will be reduced by ~50%. 
5. Write performance of a single file is limited to the performance of the storage server on which the file physically exists. 
6. Memory is read cache. 

We generally test the theoretically maximum speeds of a storage server by running iozone locally on the server without using Gluster and then over the network in clustered mode from at least 4 clients. While the iozone tests are running you should monitor resources on the storage server to find your bottleneck. If the performance of the second test matches the performance of the first then you can begin to scale the number of storage servers up to meet your total performance requirements. 

I hope I answered your questions, please let me know if you have more, I'm happy to help. We do offer a 60 day POC that includes support, please let me know if you think it might be helpful for you. - http://www.gluster.com/products/poc.php . 



Craig Carl 

Sales Engineer; Gluster, Inc. 
Cell - ( 408) 829-9953 (California, USA) 
Office - ( 408) 770-1884 
Gtalk - craig.carl at gmail.com 
Twitter - @gluster 
Installing Gluster Storage Platform, the movie! 

From: "Jonathan B. Horen" <jbhoren at alaska.edu> 
To: gluster-users at gluster.org 
Sent: Friday, September 24, 2010 2:04:39 PM 
Subject: [Gluster-users] System Requirements (and mild rant re: lack-of-documentation) 

What little documentation that there is for Gluster doesn't include anything 
regarding system requirements -- minimum or recommended. 

We're trying to spec-out a setup using four SAN storage units: two NexSans 
(30T SATAbeast and 10T SATAboy) and two FalconStors (32T NSS650 and 32T 
NSS620), all connected via iSCSI. These supply storage for two RHEL5 compute 
clusters (17-node Penguin and 3-node IBM x3950m2) and 300+ user secure file 

Without "real" documentation -- conceptual and otherwise -- it's damn 
difficult to decide. Is Gluster cpu-intensive, memory heavy, or a mix of the 
two? And bricks! Is a 10T SAN unit a "brick", or a "block" (or several 
"bricks")? and does it matter? How many bricks can/could/should a Gluster 
server node serve? 

I could spend weeks searching through the mailing-list archives, but that's 
the purpose of documentation. Frankly, we're at a loss. 

Is there information to be found, and, if so, where is it? 

Systems Administrator 
UAF Life Science Informatics 
Center for Research Services 
(907) 474-2742 
jbhoren at alaska.edu 

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