The VT-310DP Based Cluster

About This Page

This page will serve as a "project page" and scratchpad for a machine I hope to build when funds become available.

Project Status

The project is currently on hold due to lack of funds. :-(

About the Cluster

Thumbnail of the VT-310DP The cluster will be based on the VIA Technologies VT-310DP Mini-ITX and will be used for personal research into cluster-based technologies.

Proposed Cluster Usage

The cluster will initially be used as a distcc compile farm to prove its stability and then moved into a configurable system to test clustered (and distributed) applications such as Apache and database replication. Later, perhaps, the cluster will be used for folding and a render farm.

Specifications

Five VT-310DP - Four slaves and one master.
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GBP 0.00
One integrated GigE Switch, modded to use standard 12 Volt delivered by the system PSU (i.e., via molex connector). Linksys SD2005 will probably do it. GBP 55.06
Each slave will have 1GB of ram, the master will have 2GB. This Crucial.com RAM (GBP 449.94) will be used.
Five Serial ATA hard disks, four in an RAID-5 configuration for system storage, and one for standby. Ths will result in approximately 1200GB of overall cluster storage space. One small laptop IDE hard disk (40GB) will be used as the master's system disk. Preliminary browsing indicates that the Western Digital 400GB RE2 WD4000YR (review) (GBP 802.95) may be leading the pack. It would be nice to squeeze a hot swap bay (
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GBP 0.00) into the case as well. Since that bay is powered by molex style units and I'll want to, perhaps, use the PSU for powering standard Serial ATA disks (which may not have molex pins) I'll likely get a PSU with the Serial ATA connectors and simply use Serial ATA to Molex adapters!
32-bit PCI 4 port Serial ATA controller (with PCI riser). A controller with RAID-5 is probably not neceesary due to the fact that the master will be SMP and should have enough power to do the software raid. However, for such a RAID-5 controller the Promise FastTrak S150 SX4-M controller seems to be the best choice, but further investigation is required. The S150 SX4-M will run around GBP 215.01.
For power supply it has been suggested I get an Antec Trupower II 550 (GBP 90.42) and mod it to the 5 ATX connectors needed (connectors and Molex series 5556 contacts. I might also just get a custom one done from pcpowercooling as it would save having to mangle the switch, and I would be guaranteed to have the right bits working. Pity they're not based in the UK.
One enclosure.
I've been pondering this again and I wonder if I should integrate a wireless router in this system: A self-contained system with one PSU wire sticking out of it would be a very nice thing. Bearing in mind that I'm going to enclose this in one case the reception of a wifi signal would be at hand. To minimise the issue I could use "rabbit ears" (GBP 15.75) and mount this device on the case purely for aestetics. Possible wirless access points for inclusion are WRT54GS (GBP 54.48), WRT54GL (GBP 52.35) , or the more simple WAP55AG (GBP 70.17). The question is do I want to transfer gigs of data at G speeds and not wired gigabit? If the cluster is made into a scalable system then I'll need a way to interconnect cluster units (1 master and 4 slaves). Wired gigabit would be the best way especially since each board is 10/100/1000 mbit, none of the selected wireless units support gigabit.

Special Considerations

Since the cluster will have multiple applications and the slaves will rely on NAS (and not local disk storage) a mechanism of configuration replication at boot will be needed. To this end a tftp server will be running on the master which will transfer a minimal image to each slave as they boot which will then in turn set up a ramdisk, "hook up" the network storage, and copy the profile being used into the ramdisk.

The technical implications and feasibility of this boot procedure isn't known to me (yet), so the cluster will, of course, be a learning experience all around.

There's also a need to delay booting of the slaves until the master is ready for them to use the tftp and network storage. Wake-on-lan is the most obvious way to control the delay, sending the magic packet to the LAN when ready. Another less desirable method is to build a small circuit which can "press" the power button on the slaves. Unfortunately my circuit design isn't as good as it could be so this last method isn't the preferred method.

Cost is a consideration in building this cluster. I don't have the necessary GBP 3000.00 (or more) to build the system now and as time goes on it's unlikely I can afford a hardware RAID-5 controller, so it is likely that the master will use software raid and just a simple PCI serial ATA controller.

The PSU is another consideration. I will need to find a unit that can supply power to five boards, six hard disks, and the modded switch. Redundancy is also an issue. Should I bother with a backup unit?