[Lustre-discuss] Performance parameters

[Reto Gantenbein]

Hello everybody

We did experience the same issue with our file system. Metadata  
operations and operations on a big number of files are quite slow  
compared to a local or a NFS file system. For example packing the  
kernel sources takes about one and a half minutes on the 1Gbps NFS  
server, but nearly 5 minutes on our Lustre file system.

Our setup is consisting of 2 load balanced Lustre servers exporting 7  
OSTs and 1 MGS/MDT. The servers run the Lustre-patched 2.6.18 kernel  
with Lustre 1.6.4.3 self-compiled. On client side we already tried the  
2.6.22 patch-less setup and also the patched 2.6.18 kernel without  
recognizing a major performance difference. There are 192 client  
machines mounting the Lustre file system off the two servers. The MDT  
storage device is a Transtec 4Gbps FibreChannel SAS Raid. It's  
configured to use Raid level 1+0. The OSTs are Transtec 4Gbps FC SATA  
Raids, configured to use Raid 6. Each back-end device is connected for  
failover reasons to both servers via a QLogic SANbox 5602 FC switch.

The bandwidth is definitely not the bottleneck with this setup. With a  
parallel dd test, we were able to write more than 1GB/s to the OSTs.

Any hints are always welcome.

Kind regards,
Reto Gantenbein



On Jun 9, 2008, at 5:59 PM, Enrico Morelli wrote:

> On Fri, 06 Jun 2008 12:09:13 -0400
> "Brian J. Murrell" <Brian.Murrell at Sun.COM> wrote:
>
> Ok, I'm sorry but our real problem is that the system is very slow
> when the user perform 'ls' or shell commands that require access to
> metadata infos. We have about 30 person that access simultaneously to
> the system. What we can do to speed-up the system to solve this  
> problem?
> Adding another MDT can help?