Beowulf List
Don't have time to read the Beowulf List Archives. No problem, our resident List Lurker (and contributor) Jeff Layton has you covered. Our Best of the Beowulf List column provides a convenient readers Digest Version with important links!
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Choosing a Gigabit Switch
On November 11, 2003, Keyan Mehravaran said that he was connecting eight dual Xeon PC's with on-board Gigabit NICs (Network Interface Cards). He asked about the relative advantages of a managed switch versus an unmanaged switch and asked about channel bonding Gigabit NICs. An unmanaged switch is one where the management of the switch is entirely internal and cannot be configured. A managed switch is one that is configurable via an interface such as a web browser or serial terminal. Donald Becker replied that in his opinion managed switches are frequently not a good choice because the switch can be set to work in "flawed modes" that can cause problems in the future. He also explained in another posting that he thought auto-negotiation, which unmanaged switches do by default, was a good thing because it was automatic, transparent, and extensible. Moreover he pointed out that most switches are now using Ethernet flow control and users don't know this because it's configured during auto-negotiation. The bottom line is that things just seem to work better.
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This installment of the Best of the Beowulf Mailing List discusses issues about Serial ATA (SATA) drives, I/O benchmarks, cluster benchmarks, and booting from solid state USB. You can consult the archives for the actual converstions.
SATA or SCSI drives - Multiple Read/Write Speeds
There was an interesting discussion on the beowulf mailing list that started on December 8, 2003 with a posting from Robin Laing who asked about SATA drives (Serial ATA) versus IDE drives (also called Parallel ATA or PATA drives) versus SCSI drives. In particular, he wanted to know which one was better for multiple drive read and write operations. While the resulting discussion wasn't about clusters per say, disk I/O (Input/Output) performance can have a great impact on many cluster applications. Bill Broadley responded that there was some bad information and biases floating around about drive performance (e.g. IDE versus SCSI) and strongly suggested benchmarking your own code or some disk benchmark, such as Bonnie++ or Postmark (Postmark seems to have gone away), that is close to your application. He pointed out that there are many factors that can be adjusted to affect I/O performance. The discussion then broke into two parts. The first part part discussed opinions and test results of PATA and SCSI drives and controllers.
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Turning on Nodes Through the Network
On November 3, 2003, Mathias Brito posted to the Beowulf mailing list asking how he can boot the master node of his cluster and then have the slave nodes boot automatically. There were several responses to his request.
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In the fall of 2003, there was something of a general theme on the Beowulf mailing list. The theme revolved around the environment in which our clusters live. That is, the machine room. This topic involves the design of machine rooms and how to save our dear clusters from imminent disaster when the cooling fails. Join us as we take a look at killing power (quickly), building machine rooms, and environment monitoring.
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There are a huge number of mailing lists available on the Internet. The Beowulf mailing list is a resource for the cluster community. This column will summarize and expand on issues that have been discussed on the Beowulf list and also include issues from other mailing lists that are useful and pertinent to clusters. In this column we visit the Bioclusters, Beowulf, and PVFS lists. We begin our survey in summer of 2003.
