Dustin,
As always, thank you very much for your advice. I was always wanting to know what the command was to find out what volumes were available to be mounted, and I did not know about "fdisk -l". I will use that command to see if the SSD's are available. I did not see the "/mnt" disk when I did "df -h", but it may show up when I do "fdisk -l".
I tried running HYCOM using the "/mnt" disk on the master node. Since I do not know how to redirect output files to a different filesystem, I had to put all input files on the master node's "/mnt". HYCOM reads its input files and writes its output files to the same directory. I also had to put four of the smaller input files on each node's "/mnt" disk. The executable could be placed either on every node's "/mnt" disk or on a shared EBS volume. This approach works fine for the serial I/O runs where the big output files are written by MPI rank 0 which resides on the "master" node. Unfortunately, I did not see an improvement in I/O performance over using a standard EBS volume. I would have thought that a local disk would be faster than a NFS-shared EBS volume. So I am experimenting with other ideas. Actually, I am overdrawn on my AWS account, so it may be awhile before I can experiment again.
Best wishes.
Tom Oppe
________________________________________
From: Dustin Machi [dmachi_at_vbi.vt.edu]
Sent: Friday, January 04, 2013 10:44 AM
To: Oppe, Thomas C ERDC-RDE-ITL-MS Contractor
Cc: starcluster_at_mit.edu
Subject: Re: [StarCluster] Using a hi-I/O instance as the master node in a StarCluster Cluster
I've never messed with them on AWS, but I assume that these get mounted
wherever the local disks get mounted normally.../mnt. The hi1.4xlarge
should have two 1tb volumes mounted
(
http://aws.typepad.com/aws/2012/07/new-high-io-ec2-instance-type-hi14xlarge.html)
or available to mount (fdisk -l). The don't think the IOPS provisioning
will matter much here (for the the read/writes to those volumes anyway),
though they may impact the performance of the EBS volume itself of
course.
Dustin
On 4 Jan 2013, at 11:06, Oppe, Thomas C ERDC-RDE-ITL-MS Contractor
wrote:
> Dear Sir:
>
>
>
> I was wondering if anyone has tried using a high-performance I/O
> instance (e.g., "hi1.4xlarge") as the master node in a StarCluster
> cluster, with the other nodes being Sandy Bridge "cc2.8xlarge"
> instances. When I bring up a single "hi1.4xlarge" instance outside of
> StarCluster, there is an option to attach one or two 1-TB SSD disks,
> but when I bring up a cluster with "hi1.4xlarge" as the master node,
> the SSD disks are nowhere to be found. Is a plug-in necessary to ask
> for the SSD disks to be available? I have a code that needs the
> fastest I/O available for writes with a combined size of 100GB during
> the run. I have tried single Standard and Provisioned IOPS EBS
> volumes, but the I/O performance to these volumes is poor, even with
> "pre-warming". Has anyone written a plug-in for using striped volumes
> in StarCluster? I would appreciate any comments or pointers to
> information.
>
>
>
> Tom Oppe
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Received on Fri Jan 04 2013 - 18:33:35 EST