[Pc_Support] Re: MEdia Driven Universal Storage Array (MEDUSA)

[Bryan J. Smith]

On Sun, 2005-01-23 at 04:25, Jason Boxman wrote:
> Are they random 160GBs or are they the Maxtors I keep seeing?

They were Western Digitals.  Actually, I think I'm going to return the
(unopend) ones I have and get 200GB Seagate drives (I already have 2 in
use -- so I only need 3).

> Why did you choose NetCell over 3Ware?  The fast writes?

NetCell is better for desktop/appliances -- way faster at both reads and
writes, especially when you lose a disk.

> What kind of performance are you expecting for reads? Writes?

Both.  NetCell is built to take _parallel_ drives from the system bus
directly to the disks.  It's an ingenious approach that uses a _fixed_
configuration.  Either 2+1 discs for a 32-bit card, 4+1 discs for a
64-bit card -- because ATA data paths are 16-bit.  The on-board ASIC and
SDRAM then buffer and fill the dedicated parity disk.

It's not RAID-3, it's better.

> How will you deal with the issue of PCI bus bandwidth?

The 64-bit x 33MHz (266MBps) bus should suffice for the disk.

> Is the NIC on its own PCI bus or will it share it with the HD-3000?

It's only a 10/100Mbps NIC.  I am purposely _not_ putting in a 1000Mbps
NIC.  I only want to stream audio and video _after_ it is processed.  So
I only need 5MBps tops, and I won't be using it at the same time.

It will go on the 32-bit x 33MHz PCI (133MBps) slots that are bridged
off of the 64-bit PCI bus.

> I imagine the RAID card will be on a bus by itself?

I'm only going to use 

> With hardware MPEG encoding,

Nope, it's software.  But I don't plan on encoding in real-time.  I'm
going to take the "raw" 19.2MBps ATSC stream and store it.

> do you really need much bandwidth for this application?

Yes.  Ideally I wish I had PCI-X slots.  But the pcHDTV HD-3000 requires
a 5V slot.  So that's not an option.

Ideally I should consider spending $135 to get a Tyan S2466 Tiger MPX
which uses (2) 64-bit x 66MHz PCI (533MBps) 3.3V slots, and then (4)
33-bit x 33MHz (133MBps) 5V slots.  That would give me twice the
bandwidth for the NetCell card, but it's probably overkill.

I was thinking about getting one anyway, because the S2466 has better
power stability than the S2460 thanx to the 4-pin +12V plus 4-pin
Molex.  As the system heats up, the efficiency of the power supply
drops, and the sole 20-pin ATX has trouble delivering over 130W (~70A at
the voltage) to just the CPUs.  Hence why I got the PC-V1200, so the PS
is at the very bottom, drawing cool air directly from the floor.  If I
was running with my old, original 1.4GHz Athlons, or maybe even old
Durons (yes, they worked too), it wouldn't be an issue, but these latest
MP2400+ Athlons really suck up the juice (65W/piece).

If I got one, would anyone be interested in my older Tyan S2460 Tiger
MP?  64-bit (33MHz) slots, dual-CPU, etc... -- although make sure you
_do_ have a _true_ 500W+ for dual-CPU and _good_ cooling, etc...  Again,
I'd either in single mode, or if you have pre-XP processors (I
personally used 1.4GHz before, and I think older Durons will too), they
_will_ work in MP mode.  You don't need Registered memory if you only
use 1-2 DIMMs, but definitely if you're going to use 3-4 like I do.


-- 
Bryan J. Smith                                    b.j.smith at ieee.org 
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