[Lustre-discuss] Rule of thumb for setting up lustre resources...

[Brian J. Murrell]

On Sat, 2008-06-14 at 14:22 -0400, Mark True wrote:
> 
> Hello!

Hi.

> A> If increasing the number of OSTs increases throughput, is there a
> relationship that can be used to determine how many OSTs we're likely
> to need at the outset to establish a baseline minimum throughput.

Of course.

> For examples, if I want to get 3GB sustained throughput how many OSTs
> will facilitate this.

That is _completely_ dependent on your hardware configuration.  If you
are adding an "identical" (to an existing) OSTs you can simply use the
speed of the existing OST to determine how much more the new OST will
add.  But be very careful of ceilings.  You can of course only add so
many OSTs before you start to hit other resource limitations such as bus
bandwidth in the OSS and network bandwidth of the OSS's interconnect,
etc.  In short, you need to understand the performance capability of all
of your components to come up with an overall design that meets your
performance goals and scales to future goals.

> B> Does the MGS and MDS have to be separate for best performance, or
> can they be consolidated into one server without causing too much
> hardship

I'd tend to say that most people put them into the same server.  For
anything but "toy" installations however, we strongly suggest you put
the MGS and MDT on separate devices.

> C>  Right now I am looking at a model where I am connecting all the
> OSTs, and the MDS/MGS together using infiniband,

Just to keep the nomenclature straight, an OST is a device (i.e. a disk)
in/attached to an OSS.  An OSS is the server that serves OSTs.

> and connecting the storage via fibrechannel.   Is this the ideal
> solution or am I going in the wrong direction.  

That sounds suitable.

b.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
URL: <http://lists.lustre.org/pipermail/lustre-discuss-lustre.org/attachments/20080616/d8205498/attachment.pgp>