Joining SATA RAID controllers?

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

Assuming that I have two identical SATA RAID controllers, is it possible to
split a mirror set between the two controllers?

The reason I ask is because I am trying to set up a machine with 6 drives
(expandable to 8) and the 4 port controllers are much more affordable than
the 8 port ones. If I could set up say a stripe set on one controller of 3
of the drives, and mirror that set to 3 drives stripped on the other
controller, that would effectively be a 0+1 set across two controllers.

Is this just way out there, or is it feasible.

In the absence of such a solution, I'd just do a copy on a schedule or have
some backup software sync the separate sets. It would be nice to have it
happen at the hardware level though.

Thanks in advance!

--
Shawn Wilson

 

[peter]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

> Assuming that I have two identical SATA RAID controllers, is it possible
to
> split a mirror set between the two controllers?
>
> The reason I ask is because I am trying to set up a machine with 6 drives
> (expandable to 8) and the 4 port controllers are much more affordable than
> the 8 port ones. If I could set up say a stripe set on one controller of
3
> of the drives, and mirror that set to 3 drives stripped on the other
> controller, that would effectively be a 0+1 set across two controllers.
>
> Is this just way out there, or is it feasible.
>
> In the absence of such a solution, I'd just do a copy on a schedule or
have
> some backup software sync the separate sets. It would be nice to have it
> happen at the hardware level though.

Like ARIO-FST?
www.ariodata.com/products/pdfs/fst.pdf

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

In comp.sys.ibm.pc.hardware.storage Shawn Wilson <shawnw_nospam_@_nospam_dvigroup.net> wrote:
> Assuming that I have two identical SATA RAID controllers, is it possible to
> split a mirror set between the two controllers?

> The reason I ask is because I am trying to set up a machine with 6 drives
> (expandable to 8) and the 4 port controllers are much more affordable than
> the 8 port ones. If I could set up say a stripe set on one controller of 3
> of the drives, and mirror that set to 3 drives stripped on the other
> controller, that would effectively be a 0+1 set across two controllers.

> Is this just way out there, or is it feasible.

It might be feasible, but it could create immense bus-load and it would
be difficult, since two bus masters would need to communicate with each
other at high speed and with a lot of data-flow reversals. I assume that
most reasonable controllers (side-note: Adaptec SATA is trash) will not
do this.

There are (or were) some exotic solutions out there that could do what
you want but with the controllers and sisk being in two different
computers and with a dedicated fast datalink between the two cards.

> In the absence of such a solution, I'd just do a copy on a schedule or have
> some backup software sync the separate sets. It would be nice to have it
> happen at the hardware level though.

Depending on the OS you use, why not do the RAID 1 layer in software
on top of two independent arrays? Or why not do the whole thing in
software? I have an array with two promise sata 150tx4 and software
RAID 5 under Linux.

Arno

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

"Arno Wagner" <me@privacy.net> wrote
Shawn Wilson <shawnw_nospam_@_nospam_dvigroup.net> wrote:
>> Assuming that I have two identical SATA RAID controllers, is it possible
>> to
>> split a mirror set between the two controllers?
>
>> In the absence of such a solution, I'd just do a copy on a schedule or
>> have
>> some backup software sync the separate sets. It would be nice to have it
>> happen at the hardware level though.
>
> Depending on the OS you use, why not do the RAID 1 layer in software
> on top of two independent arrays? Or why not do the whole thing in
> software? I have an array with two promise sata 150tx4 and software
> RAID 5 under Linux.
>
> Arno

That makes a lot of sense... I'll just set up the two controllers
identically but seperate, then use software RAID to mirror one to the other.

I like the idea of hardware RAID in general, but for this part of it,
software RAID solves the problem.

Thanks.

--
Shawn Wilson

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

"Arno Wagner" <me@privacy.net> wrote in message news:3oe3lpF5iu9nU2@individual.net
> In comp.sys.ibm.pc.hardware.storage Shawn Wilson <shawnw_nospam_@_nospam_dvigroup.net> wrote:
> > Assuming that I have two identical SATA RAID controllers, is it possible to
> > split a mirror set between the two controllers?
>
> > The reason I ask is because I am trying to set up a machine with 6 drives
> > (expandable to 8) and the 4 port controllers are much more affordable than
> > the 8 port ones. If I could set up say a stripe set on one controller of 3
> > of the drives, and mirror that set to 3 drives stripped on the other
> > controller, that would effectively be a 0+1 set across two controllers.
>
> > Is this just way out there, or is it feasible.
>
> It might be feasible, but it could create immense bus-load and it would
> be difficult, since two bus masters would need to communicate with each
> other at high speed and with a lot of data-flow reversals.

What a load of nonsense.
That is no more different than software mirroring

> I assume that most reasonable controllers (side-note: Adaptec SATA is
> trash) will not do this.

The 'reasonal' ones might, the cheaper ones may not.
It is not uncommon for Host Adapter built-in Setup utilities to control
more than one Host Adapter. The ones that do may just behave like it was
a single 4 (or more) channel controller.

>
> There are (or were) some exotic solutions out there that could do what
> you want but with the controllers and sisk being in two different
> computers and with a dedicated fast datalink between the two cards.
>
> > In the absence of such a solution, I'd just do a copy on a schedule or have
> > some backup software sync the separate sets. It would be nice to have it
> > happen at the hardware level though.
>
> Depending on the OS you use, why not do the RAID 1 layer in software
> on top of two independent arrays? Or why not do the whole thing in
> software? I have an array with two promise sata 150tx4 and software
> RAID 5 under Linux.
>
> Arno

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

yes u can do that with linux and soft based raid. Onily u have to see if u
can mix hw raid inside each controller and then sowtware raid among
controllers.

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

In comp.sys.ibm.pc.hardware.storage Shawn Wilson <shawnw_nospam_@_nospam_dvigroup.net> wrote:
> "Arno Wagner" <me@privacy.net> wrote
> Shawn Wilson <shawnw_nospam_@_nospam_dvigroup.net> wrote:
>>> Assuming that I have two identical SATA RAID controllers, is it possible
>>> to
>>> split a mirror set between the two controllers?
>>
>>> In the absence of such a solution, I'd just do a copy on a schedule or
>>> have
>>> some backup software sync the separate sets. It would be nice to have it
>>> happen at the hardware level though.
>>
>> Depending on the OS you use, why not do the RAID 1 layer in software
>> on top of two independent arrays? Or why not do the whole thing in
>> software? I have an array with two promise sata 150tx4 and software
>> RAID 5 under Linux.
>>
>> Arno

> That makes a lot of sense... I'll just set up the two controllers
> identically but seperate, then use software RAID to mirror one to the other.

> I like the idea of hardware RAID in general, but for this part of it,
> software RAID solves the problem.

> Thanks.

No problme.

Arno

 

[Guest]

Archived from groups: comp.sys.ibm.pc.hardware.storage,it.comp.hardware.storage (More info?)

These PCI 4-ports are software RAID, same as Windows built-in.

Just do the RAID 1 on the controller and RAID 0 in Windows.

"Shawn Wilson" <shawnw_nospam_@_nospam_dvigroup.net> wrote in message
news:8tjUe.174406$Lg2.139104@fe12.news.easynews.com...
> Assuming that I have two identical SATA RAID controllers, is it possible to
> split a mirror set between the two controllers?
>
> The reason I ask is because I am trying to set up a machine with 6 drives
> (expandable to 8) and the 4 port controllers are much more affordable than
> the 8 port ones. If I could set up say a stripe set on one controller of 3
> of the drives, and mirror that set to 3 drives stripped on the other
> controller, that would effectively be a 0+1 set across two controllers.
>
>