hardware for home use large storage

[Pieter de Goeje]

On Wednesday 10 February 2010 05:28:57 Dan Langille wrote:
> Boris Kochergin wrote:
> > Peter C. Lai wrote:
> >> On 2010-02-09 06:37:47AM -0500, Dan Langille wrote:
> >>> Charles Sprickman wrote:
> >>>> On Mon, 8 Feb 2010, Dan Langille wrote:
> >>>> Also, it seems like
> >>>> people who use zfs (or gmirror + gstripe) generally end up buying
> >>>> pricey hardware raid cards for compatibility reasons.  There seem to
> >>>> be no decent add-on SATA cards that play nice with FreeBSD other
> >>>> than that weird supermicro card that has to be physically hacked
> >>>> about to fit.
> >>
> >> Mostly only because certain cards have issues w/shoddy JBOD
> >> implementation. Some cards (most notably ones like Adaptec 2610A which
> >> was rebranded by Dell as the "CERC SATA 1.5/6ch" back in the day)
> >> won't let you run the drives in passthrough mode and seem to all want
> >> to stick their grubby little RAID paws into your JBOD setup (i.e. the
> >> only way to have minimal
> >> participation from the "hardware" RAID is to set each disk as its own
> >> RAID-0/volume in the controller BIOS) which then cascades into issues
> >> with SMART, AHCI, "triple caching"/write reordering, etc on the
> >> FreeBSD side (the controller's own craptastic cache, ZFS vdev cache,
> >> vmm/app cache, oh my!). So *some* people go with something
> >> tried-and-true (basically bordering on server-level cards that let you
> >> ditch any BIOS type of RAID config and present the raw disk devices to
> >> the kernel)
> >
> > As someone else has mentioned, recent SiL stuff works well. I have
> > multiple http://www.newegg.com/Product/Product.aspx?Item=N82E16816132008
> > cards servicing RAID-Z2 and GEOM_RAID3 arrays on 8.0-RELEASE and
> > 8.0-STABLE machines using both the old ata(4) driver and ATA_CAM. Don't
> > let the RAID label scare you--that stuff is off by default and the
> > controller just presents the disks to the operating system. Hot swap
> > works. I haven't had the time to try the siis(4) driver for them, which
> > would result in better performance.
> 
> That's a really good price. :)
> 
> If needed, I could host all eight SATA drives for $160, much cheaper
> than any of the other RAID cards I've seen.
> 
> The issue then is finding a motherboard which has 4x PCI Express slots.  ;)

You should be able to put PCIe 4x card in a PCIe 16x or 8x slot. 
For an explanation allow me to quote wikipedia:

"A PCIe card will fit into a slot of its physical size or bigger, but may not 
fit into a smaller PCIe slot. Some slots use open-ended sockets to permit 
physically longer cards and will negotiate the best available electrical 
connection. The number of lanes actually connected to a slot may also be less 
than the number supported by the physical slot size. An example is a x8 slot 
that actually only runs at ×1; these slots will allow any ×1, ×2, ×4 or ×8 
card to be used, though only running at the ×1 speed. This type of socket is 
described as a ×8 (×1 mode) slot, meaning it physically accepts up to ×8 cards 
but only runs at ×1 speed. The advantage gained is that a larger range of PCIe 
cards can still be used without requiring the motherboard hardware to support 
the full transfer rate—in so doing keeping design and implementation costs 
down."

-- Pieter