[Novalug] best hard disk setup for home file server?

Bryan J. Smith b.j.smith@ieee.org
Wed Oct 14 23:58:12 EDT 2009


Just a disclaimer ... I am _not_ suggesting you buy the RocketRAID 2640 series.
There could be real support issues with most Linux distros, as the driver is still
maturing from what I've read.

I was just commenting how that $60 price is a bit up there with SAS host adapters
that start just under (and just over) $100.  At some point I'm going to break down
and see what is and isn't in those low-cost Marvell ASICs by getting one myself.

I know they can do RAID-0, 1 and 0+1/10 (including 2-disc) right in the ASIC+
SRAM, only faster than 3Ware's old ASICs (with on-IC FPGA, they can literally
reprogram the ATA controllers, and did so for LBA48 support in ATA-6 on existing
units when others were stuck at only 128GiB/137GB support).  I suspect they won't
be very good for RAID-5 with the lack of buffer, possibly limitations with the design
too.

Which makes me wonder where the Linux support is at.  It seems most people
who know what they are doing can get the GPL driver built, but the user-space
support is lacking for hardware RAID (e.g., array management, etc...).


----- Original Message ----
From: Bryan J. Smith <b.j.smith@ieee.org>

Ack, at $60 you're almost to a Marvell ASIC-based SAS host adapter ($80):  
  http://www.newegg.com/Product/Product.aspx?Item=N82E16816115053  

The only kicker with going the newer SAS host adapter route is that the drivers
are still making it into the distros.  It's also only got a limited amount of SRAM
in the IC, no DRAM on-board, so I don't know how well the lack of on-card
buffer will do.  But it's clear the Broadcom, Marvell and other PCIe-to-SAS
"storage switches" have some real intelligence (and the SCSI-2 command
set -- i.e., SAS is Serial ATA + SCSI-2 instead of being a "dumb block" ATA).

Tom's Hardware liked the exact same model, only tested the PCIe x4 lane version ($10 more):  
  http://www.newegg.com/Product/Product.aspx?Item=N82E16816115050  

Review is here:  
  http://www.tomshardware.com/reviews/sas-adaptec-highpoint,2101.html  

I've been tempted to try one of these out because my K8N-LR has an available
PCIe x8 slot (the one where the x16 was split off into x8 for PCIe x8 and other
x8 to the Intel IXH/ESB for PCI-X bridge).  I just want to see what kind of capability
is in those SAS host adapters.



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