Re: [LUAU] Favorite SATA or PATA RAID controllers

[Julian Cowley]

On Wed, 10 Feb 2010, R. Scott Belford wrote:
On Wed, Feb 10, 2010 at 4:30 PM, Clifton Royston <clift...@lava.net> wrote:
On Wed, Feb 10, 2010 at 12:22:20PM -1000, Brian Chee wrote:
> I need to mirror (RAID 1) and was wondering about the collective option
on
> PCI RAID controllers....
>
> These are going into 1RU SuperMicro machines that tend to run hot....so
that
> is a bit of a consideration. I¹d like to use the same RAID controller for
> both Windows 2003 Server AND Debian Linux both...
>
> /brian chee

  Even though you're looking for Linux supported cards, there's a thread
on freebsd-stable right now you might want to look through, discussing
reliable inexpensive SATA controllers.

 Thread title is: "hardware for home use large storage"

 For BSD or Linux machines, I tend to think you're just as well off
with software RAID, at least until you get to fairly high-end systems
(e.g. external enclosures with their own RAID controllers.) If the card
has to do RAID under Windows, though, hardware RAID may be the only
reasonable option.


In answer to the original question, I use High Point SATA RAID controllers
when the need arises, and I depend on 3WARE for ATA RAID support.  Unless
you intend to benefit from the battery on board a RAID card while maximizing
all CPU cycles, there is rarely a good case for a single RAID card.  I used
to run Bonnie++ tests on both, and the NCQ feature of SATA 3.0 and SAS
drives close any lingering gaps.

Cliff's suggestion is supported by multiple platforms, and it is so hard to
beat the performance of a Software RAID10 array.  Software RAID allows for
multiple hot spares, array repair without rebooting, and the admin and
reporting tools once found only in RAID cards.  If you are going to use
redundant HW RAID cards, or keep a cold spare on site, and maximize all CPU
cycles for your applications, then your needs likely necessitate the RAM,
CPU, and Battery of a RAID controller or two.

Here is a link I keep on-hand to remind myself why I prefer software RAID. 
To me, the benefits of software RAID far outweigh the drawbacks.

- Linux: Why software RAID? by Jeff Garzik (one of the Linux kernel
  developers who specializes in writing SATA drivers)

  http://linux.yyz.us/why-software-raid.html

It has saved our butts at least once, too.  One time, a machine failed on 
us, and I needed to transfer the physical drives from one machine to 
another.  The failed machine had a proprietary 3ware card on the 
motherboard, and the other one didn't, so I was expecting the worst. 
Fortunately we had configured the disks as JBOD with Linux MD RAID and I 
was able to transfer the drives to the new machine and get them running 
quickly without having to buy a new 3ware card.

To add more to the mix, here's a comparison of hardware and software
RAID on Linux:

- Benchmarking hardware RAID vs. Linux kernel software RAID

  
http://www.linux.com/news/hardware/servers/8222-benchmarking-hardware-raid-vs-linux-kernel-software-raid_______________________________________________
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