Hardware raid question (do I need a 4-port card)

[godfatherofsoul]

I've got 4X60 GB identical drives that I'd like to use for home office
RAID in an XP server box. I've looked on eBay and found a ton of cheap
2-port IDE cards that claim to support up to 4 IDE devices. I
understand the RAID levels, but I don't follow how a card with 2 ports
can support 4 devices. Does it somehow detect and use the existing IDE
ports on the motherboard (which would suck for me since I already have
the OS on one of those ports)? Or does make use of two slave drives
(which sounds slow)? Any help or direction to a good resource is
appreciated!

 

[Rod Speed]

I've got 4X60 GB identical drives that I'd like to use for home
office RAID in an XP server box. I've looked on eBay and
found a ton of cheap 2-port IDE cards that claim to support
up to 4 IDE devices. I understand the RAID levels, but I
don't follow how a card with 2 ports can support 4 devices.

You can have 2 drives per port.

Does it somehow detect and use the
existing IDE ports on the motherboard
Nope.

(which would suck for me since I already
have the OS on one of those ports)?

Or does make use of two slave drives

Yes, two drives per port.

(which sounds slow)?

Certainly slower than 1 drive per port, anyway.

 

[Folkert Rienstra]

I've got 4X60 GB identical drives that I'd like to use for home office
RAID in an XP server box. I've looked on eBay and found a ton of cheap
2-port IDE cards that claim to support up to 4 IDE devices.

I understand the RAID levels,

You do?

but I don't follow how a card with 2 ports can support 4 devices.

Why not? Maybe you don't understand the RAID levels afterall?

Two RAID1 drives will not be a problem at all.

Two RAID-0 neither, as long as you don't read-access them simultaniously.

For long sequential reads it's not a big problem again, since only the
first access is serialized, next come from read ahead cache.

Single logical drive RAID (none mirror) may not be a good idea but again
the problem is mostly with reads, not writes.

Does it somehow detect and use the existing IDE ports on the mother-
board (which would suck for me since I already have the OS on one of
those ports)?

Or does make use of two slave drives

Master OR Slave has nothing got to do with it. Master AND Slave does
and Master (device0) is just as vulnarable as Slave (device1) is. As long
as one of them is busy the next command can't be delivered to the other,
whether device0 or device1. With writes it is different as the drive is
ready and the bus free as soon as the command/data have been delivered.

 

[Frazer Jolly Goodfellow]

You do?

A 2-port IDE card *will* support 4 physical IDE devices, just like
the onboard IDE controller of a motherboard does. Master and slave
devices can be connected to each port, via standard 2-connector
ribbon cables. 2 x 2 = 4

Why not? Maybe you don't understand the RAID levels afterall?

Or maybe you've missed the bleedin' obvious.