Date: Wed, 10 Feb 2010 02:55:16 -0800 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: freebsd-stable@freebsd.org Subject: Re: hardware for home use large storage Message-ID: <20100210105516.GA65506@icarus.home.lan> In-Reply-To: <201002101127.53444.pieter@service2media.com> References: <4B6F9A8D.4050907@langille.org> <4B718EBB.6080709@acm.poly.edu> <4B723609.8010802@langille.org> <201002101127.53444.pieter@service2media.com>
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On Wed, Feb 10, 2010 at 11:27:53AM +0100, Pieter de Goeje wrote: > 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." Correction -- more than likely on a consumer motherboard you *will not* be able to put a non-VGA card into the PCIe x16 slot. I have numerous Asus and Gigabyte motherboards which only accept graphics cards in their PCIe x16 slots; this """feature""" is documented in user manuals. I don't know how/why these companies chose to do this, but whatever. I would strongly advocate that the OP (who has stated he's focusing on stability and reliability over speed) purchase a server motherboard that has a PCIe x8 slot on it and/or server chassis (usually best to buy both of these things from the same vendor) and be done with it. -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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