Saturday, April 28, 2007

Starter kit for an iSCSI SAN

Now that it's spring, it's time for us to start building out our preliminary iSCSI SAN unit. Here's the hardware shopping list:

$0600 Super Micro 4U/TOWER RM EATX BLACK ( CSE-942I-R760B )
- triple-module redundant PSU w/ 760W
- 4U case for either rack or tower use
- (9) 5.25" bays

$0020 20-pin front panel connector to breakout cable
- Converts the 20-pin connector to something that can be attached to normal ATX motherboards
- CBL-0067 30cm
- CBL-0085 15cm

$0050 Rackmount Rail Kit: CSE-PT26

$0320 (2) Spare PSU modules - PWS-0050(M)
- Spare PSU modules for the redundant PSU
- Useful to have a spare or two on-hand

$0600 (4) CSE-M35T1 (black) - SuperMicro SATA 5:3 backplanes
- These allow you to fit a total of (15) SATA drives into the (9) 5.25" bays
- There are other SATA 5:3 backplanes that you can use
- While we're only going to install (3) of these backplanes, I recommend buying a 4th for spare parts

$0167 3848163 (1) INTEL PRO/1000 PT DUAL PORT EXPI9402PT gigabit PCIe x4
- Used for SAN traffic
- Eventually, we'll upgrade to a quad-port PCIe or a 10GigE

$0167 1494573 (1) INTEL PRO/1000 PCI-X
- The PCI card is used to talk to the LAN and internet, no SAN traffic will flow over it
- You could use an inexpensive 10/100 PCI card, but with a dual-port NIC you can bond for high-availability

$0600 12-port Promise SATA-II PCIe x8 card EX12350
- CentOS5 automatically sees any drives attached to this card (when they are configured in JBOD mode)
- We're going the SoftwareRAID route

$0305 TYAN S2927G2NR dual-Opteron Socket F Thunder n3600B (S2927)
$0600 Opteron 2214 dual-core Socket F
$0200 (2) 1GB memory modules
$0100 (2) Socket F cooling fans (Cooljag CJC689C)
- (4) 1.8GHz cores should be plenty of horsepower to do use Software RAID instead of the Promise RAID software
- 2GB is probably minimal for RAM, 4GB would be better

$1800 (15) 500GB SATA-II drives
- 500GB is a good balance between price and capacity

Totals:

$3410 base system
$1800 drives

...

The drive plan for this unit is:

(3) 500GB drives in 3-way RAID1 (mirrored) for the operating system, log files, and other support software

Either:

(10) RAID10 + (2) hot-spares
(2) 5-disk RAID6 + (2) hot-spares

The pair of RAID6 arrays would give us about 20% more capacity (net of 6 disks vs 5 disks). So the RAID10 setup results in around 2.27TB while the RAID6 setup would give 2.72TB.

With an overall cost of around $5500 for the entire unit, the price per gigabytes end up as:

$2.36/GB for (1) RAID10 array
$1.97/GB for (2) RAID6 arrays

Which is not terribly bad for a starter unit.