Date: Sat, 05 May 2007 08:17:41 -0700
From: Richard Elling <[EMAIL PROTECTED]>
Harold Ancell wrote:
At 04:41 AM 5/5/2007, Christian Rost wrote:
For what and when to buy, I observe two things: at some point you
HAVE to buy something; with disks exceeding Moores Law (aren't
they at about a doubling every 12 months instead of 18?), you're
going to feel some pain afterwards *whenever* you purchase as
prices continue to plummet. From that, many say buy what you have
to buy when you have to, although that isn't so useful if growing
a RAID-Z is difficult....
Disk prices remain constant.
After checking my spreadsheets for the last eight years, you're right;
I hadn't looked at it that way. And it's an important point.
Disk densities change. With 500 GByte disks in the $120 range, they
are on the way out, so are likely to be optimally priced. But they
may not be available next year. If you mirror, then it is a
no-brainer, just add two.
A good point---but how realistic is the concern that 500GB drives will
go "poof"? I guess the question is "who buys them"? Lower size disks
stay in production because people now only "need" X disk space today,
where X is *currently* below 500GB.
I checked Dell.com, and their "we want you to buy this higher end home
machine" offer has a 320GB stock drive, but highlights a 500GB just
below it with a bolded "Dell recommended for photos, music, and
games!", for an extra 120 US$, about 10% of the machine's price.
I'll bet a lot of people take them up on that.
[ Query on solid host PCI/PCIe multiple SATA adaptors. ]
Look for gear based on LSI 106x or Marvell (see marvell88sx). These
are used in Sun products, such as thumper.
The LSI 106[48] are PCI-X chips and the Marvell driver is for PCI-X as
well, according to http://www.sun.com/bigadmin/hcl/driverlist.html and
some searching of this list's archives. Also, as of last year the
latter (or most likely its driver) seemed to have some bugs---and is
closed source, so we can't fix them :-(.
The LSI 106[48]e are a possibility: the 8 SAS/SATA port LSISAS1068E
would seem to be the interesting chip. It uses the existing LSI Logic
Fusion-MPT software infrastructure.
LSI makes RAID 0, 1, 1E and 10E only cards; they have a product matrix
of their PCI-X and PCIe el cheapo cards at:
http://www.lsi.com/storage_home/products_home/host_bus_adapters/sas_hbas/index.html
It has four PCI Express parts listed at the bottom: below find the
model name, Kit/Single Part number, and date for the "product brief"
glossy brochure, prices for a retail kit from scsi4me.com (no
endorsement there, they are just the first distributor I found that
carries these, be warned they list prices for 5 unit bulk packs, you
have to select the retail kit on the "Condition" drop box):
LSISAS3041E-R, LSI00112, 4 internal, 12/06. 70 US$.
LSISAS3442E-R, LSI00110, 4 external and 4 internal, 10/06, 109 US$.
LSISAS3801E, LSI00138, 8 external 02/07 (Google returns only 13
English hits on this model name, very new indeed).
LSISAS3081E-R, LSI00151, 8 internal, none, does not seem to be shipping yet.
The LSI SAS3442E-R would seem to be their first released card:
http://www.lsi.com/storage_home/products_home/host_bus_adapters/sas_hbas/lsisas3442er/index.html
http://www.lsi.com/files/docs/marketing_docs/storage_stand_prod/sas/LSISAS3442E-R_PB.pdf
LSI SAS3442E-R
PCI Express, 3 Gb/s, SAS, 8-port Host Bus Adapter
The LSI SAS3442E-R four-port internal/four-port external SAS PCI
Express storage adapter provides 300 MB/s bandwidth (600 MB/s, full
duplex) on each port for combined throughput of up to 2.4 GB/s. The
storage adapter supports multi-volume OS independent Integrated RAID
0, 1, 1E and 10E without the need for special drivers. The
SAS3442E-R features PCI Express connectivity, removing the host bus
bottleneck from the parallel PCI busses.
* LSI LSISAS3442E-R KIT - PCI Express, 3 Gb/s, 8-port, SAS
- Individually packaged box with LSI LSISAS3442E-R HBA, CD
containing drivers, (1) internal cable for connecting to (4) SAS
hard disk drives, (1) internal cable for connecting to (4) SATA
HDD or SATA-style backplane connectors, low-profile bracket, and
quick installation guide
- Part Number: LSI00110
One fly in the ointment for me at the moment: these have one PCIe lane
per supported port, x4 or x8; this is not insane, with SAS topologies,
the larger boards can be connected to up to 1023 devices (!!!, and see
below), which would allow only one card in the motherboard I'm
thinking of buying for my ZFS fileserver (the Tyan Tomcat K8E S2865).
If the single SATA port to multiple SATA drive enclosure problem can
be solved, this would not prove to be much if any of a limitation,
depending on how much traffic these first generation cards can handle,
and how many disks per enclosure. The Seagate 7210.10 SATA Product
Manual says the "Sustained data transfer rate OD" for 500MB drives is
72MB/s (750GB is 78MB/s). One PCIe lane will handle 250MB/s, about
3.5 time that, so the raw transfer numbers are there....
(I'm interested in these limits because I *desire* to have a RAID-Z
system feed a Quantum LTO-3 tape drive at it's full native 68MB/s (it
will step down if that isn't possible).)
Has anyone tried one of these LSI PCIe cards? I checked this mailing
list and storage-discuss for each one, and only found these:
Date: Tue, 17 Oct 2006 13:24:55 -0700
From: Frank Cusack <[EMAIL PROTECTED]>
Subject: Re: Re: ZFS Inexpensive SATA Whitebox
Message-ID: <[EMAIL PROTECTED]>
[...] For example, I've had a devil of a time trying to get the LSI
3442-E working on Solaris SPARC (works on x86 with LSI driver)....
Date: Fri, 19 Jan 2007 23:23:49 -0800
From: Frank Cusack <[EMAIL PROTECTED]>
Subject: Re: External drive enclosures + Sun Server for mass storage
Message-ID: <[EMAIL PROTECTED]>
On January 19, 2007 5:59:13 PM -0800 "David J. Orman"
<[EMAIL PROTECTED]> wrote:
> card that supports SAS would be *ideal*,
Except that SAS support on Solaris is not very good.
One major problem is they treat it like scsi when instead they should
treat it like FC (or native SATA).
> So, anybody have any good suggestions for these two things:
>
># 1 - SAS/SATA PCI-E card that would work with the Sun X2200M2.
I had the lsilogic 3442-E working on x86 but not reliably. That is
the only SAS controller Sun supports AFAIK.
[...]
Which are ambiguous about the target being SATA or SAS, although
probably the former.
What I've found so far on this list is that if you want multi-port
non-PCI-X SATA, get a Silicon Image chip based card, e.g. the Si3114
(SATA 150 though :-( ), and flash its BIOS to IDE if it comes with the
RAID BIOS. At 22 US$ from NewEgg, that "works for me!" until there is
a better solution.
- Harold
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