[svlug] Multi drive PCI SATA card or 6 port SATA motherboard

Rick Moen rick at linuxmafia.com
Mon Mar 13 16:31:57 PST 2006

Quoting Marc MERLIN (marc_news at merlins.org):

> Right now, it looks like this is what I need:
> http://store.yahoo.com/iwin2win/pcise4xposar.html
> along with a port multiplier, that was the magic:
> http://store.yahoo.com/fire-wire-1394-ilink/saiipomupcbf.html
> The combo _apparently_ works with linux 

You'll notice that my page has _some_ information about whether
particular Linux mass-storage drivers include support for port
multipliers aka port multiplexers.  That's a SATA-II-era enhancement
that snuck up on me:  I started seeing references to chips to implement
it, but for a long time there was a total lack of information about the
nature of the driver ramifications.  After verifying that there _is_ a
potential driver issue, I've tried to include information for all
listings, as I find it.  As you'll see, information so far has been very

My page so far hasn't said much about eSATA (extensions for external
devices), either.

> "100 MB/sec RAID 5 sequential writes" is sad though, it's barely 2 drives'
> worth of bandwidth. At $700 for the card, I don't seem the point when I'm
> sure I can beat that with software raid.

The prime reason for 3Ware's flagship 9550 series seems to be that the
900x/8xxx series both lacked the raw throughput of more recent offerings
from HW-RAID competitors such as Areca -- but in PCI-X and PCIe form
factors only, for obvious reasons of system bus capacity.  If I were
spending money on that and wanted performance, I might see what Tekram
offers paralleling Areca's product line.  (Of course, I'd need a modern
motherboard, first.  If someone had the sense to build ~6-8 really good
SATA connections _into_ a motherboard, that'd be even better, but I don't
expect that.)

> It looks like for now one $20 Sil 3124 with a couple of 5 port multipliers
> will give me 12 ports for about $220, with the flexibility of moving the 
> port multipliers to other systems as I need to move the drives around, and
> while sticking to a simple PCI card (anything else would be a waste of
> money since it won't be able to use the non existent MB I/O)
> It's just slightly unclear how well the port multiplier works with linux,
> but apparently, it's supposed to.

Any good sources of information you can refer me to, on such matters,
would be appreciated.

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