[mythtv-users] Question re: available SATA ports and linux software RAID

Bobby Gill brownitus at gmail.com
Fri Apr 8 03:59:56 UTC 2011

> At work I have these cards in JBOD mode so they show up as individual
> disks. Then I use software linux raid 6 with the individual drives.
> BTW, These cards require 2 special cables SFF-8087 to 4 x 7pin SATA
> forward cables.
> http://www.newegg.com/Product/Product.aspx?Item=N82E16812228057&cm_re=sas_cable_8087-_-12-228-057-_-Product
> http://www.newegg.com/Product/Product.aspx?Item=N82E16812228056&cm_re=sas_cable_8087-_-12-228-056-_-Product
> On eBay you can get these for less than $15 for 3ware ones. Here is a
> Google search for these.
> http://www.google.com/products/catalog?hl=en&client=firefox-a&hs=huy&rls=org.mozilla:en-US:official&q=3ware+sas+8087&bav=on.2,or.r_gc.r_pw.&um=1&ie=UTF-8&cid=17016499459874477598&sa=X&ei=7z-eTfCdHOXo0gHnx8HaBA&ved=0CCMQ8wIwAg#
> John
Thanks! So basically in BIOS you set it to JBOD and then go about the array
in linux?

And are those the same cables just measuring differently at 18/36 or do I
need one of each? Look the same to me, but just checking.

Some people hate downtime even when the OS-disk fails, most choose to solve
> that by using a raid1 volume as boot. It makes failure a bit les
> destructive...

Ahh, RAID-1 sounds a rather good idea for the OS. I could make use of some
320GB's lying around. Thanks for that!

>  Yup, put it in IT-mode and it'll pass on the disks to the OS. You'll need
> SFF-8087 cable to 7 pin SATA for that though(can be had cheaply via ebay)

IT-mode is setting the card to use software RAID, right?

> They're prefferably 100% the same, but if you foresee mixing and matching:
> create partitions that are just a bit smaller than the disk-size to give
> yourself some room to play with. So on 2 TiB make the partition something
> likt 1990 GiB., then you can do some mixing and matching easier. I'd advise
> 1 or two, recently had a failure and chucked in another disk, had it rebuild
> and now have time to RMA the other one.  if you wait longer and another disk
> fails you're on thin ice rebuilding(which hammers the disks).
> Jos

So if the size is the same does it matter what brand/model is being used? I
don't plan on putting any less than 2TB in the array, so if for example I
have 8 x Spinpoint F2 and one fails, could I put in a WD 2TB?

On Thu, Apr 7, 2011 at 6:25 PM, Bobby Gill <bobbygill at rogers.com> wrote:
> > if I have 8x2TB for example in RAID6, I'd have 12GB usable.
> Wow, that's some serious redundancy.
> (Sorry, I couldn't resist.  Of course you meant 12TB.)
> Eric

Haha! Caught me, well done :)

it was a bitch to setup. See my post below on how to get around
> HighPoint's fake JBOD setup.
> http://www.mythtv.org/pipermail/mythtv-users/2011-March/311656.html
> The supplied driver from HighPoint is is not compatible with 2.6.37
> kernel due to a change in queuecommand not requiring scsi locks. This
> will cause your OS to crash hard on boot. See the blog below from a user
> who enlighten me about the issue. Patch also included. All communication
> to HighPoint have gone unanswered.
> http://blog.nielshorn.net/2011/03/vhba-and-rocketraid-2320-rr232x-modules-with-kernel-2-6-37-x/
This is very disappointing, as I received a rather prompt response from
HighPoint, but I can wager it was due to such a simple question and not what
I'll also wager is a more severe lack of support in this situation you
mention :(

> I am also shopping around for a 8 port SATA adaptor. I have settled on a
> card with the LSI SAS2008 chipset due to >3TB drive support. The Intel
> card recommended uses the LSI SAS1068E chipset and does not support >3TB
> drives. If you decided to expand your array with these drives shop
> around on ebay for LSI 9240, IBM M1015 or Intel RS2WC080. These three
> cards are identical, however the IBM card runs a cripple firmware with
> RAID5/50 disable (which you won't need anyway) and is available for a
> lot cheaper that the other two. Lots of unused, freshly pulled cards
> available. One warning, LSI cards can be picky with motherboards.

Another excellent tip, thanks! So LSI SAS2008 it is. And by crippling
RAID5/50 that would be for hardware RAID thus not affecting a would-be linux
software RAID user as myself, right?

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