Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Johannes Ruscheinski]

Hi,

We're looking for a low-cost high-reliability IDE RAID solution that works well
with the 2.6.x series of kernels.  We have about 1 TB (8 disks) that we'd
like to access in a non-redundant raid mode.  Yes, I know, that lack of
redundancy and high reliability are contradictory.  Let's just say that
currently we lack the funding to do anything else but we may be able to obtain
more funding for our disk storage needs in the near future.
-- 
TIA,
Johannes
--
Dr. Johannes Ruscheinski
EMail:    ruschein_AT_infomine.ucr.edu ***          Linux                  ***
Location: science library, room G40    *** The Choice Of A GNU Generation! ***
Phone:    (909) 787-2279

Outlook, n.:
        A virus delivery system with added email functionality.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Joel Jaeggli]

well if you currently have 1tb in 8 non-redundant drives then you using 
160GB disks... no?

the biggest p-ata disks right now are ~320GB so you can do a ~1TB software 
raid 5 stripe on a single 4 port ata controller such as a promise tx4000 
using regular software raid rather than the promise raid. that would end 
up being fairly inexpensive and buy you more protection.

linux software raid hsa been as releiable as anything else we've used over 
the years, the lack of reliabilitiy in your situation will come entirely 
from failing disks, lose one and your filesystem is toast.

joelja

On Sun, 28 Dec 2003, Johannes Ruscheinski wrote:

> Hi,
> 
> We're looking for a low-cost high-reliability IDE RAID solution that works well
> with the 2.6.x series of kernels.  We have about 1 TB (8 disks) that we'd
> like to access in a non-redundant raid mode.  Yes, I know, that lack of
> redundancy and high reliability are contradictory.  Let's just say that
> currently we lack the funding to do anything else but we may be able to obtain
> more funding for our disk storage needs in the near future.
> 

-- 
-------------------------------------------------------------------------- 
Joel Jaeggli  	       Unix Consulting 	       joelja@darkwing.uoregon.edu    
GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Johannes Ruscheinski]

Also sprach Joel Jaeggli:
> well if you currently have 1tb in 8 non-redundant drives then you using 
> 160GB disks... no?
> 
> the biggest p-ata disks right now are ~320GB so you can do a ~1TB software 
> raid 5 stripe on a single 4 port ata controller such as a promise tx4000 
> using regular software raid rather than the promise raid. that would end 
> up being fairly inexpensive and buy you more protection.

Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
hardware raid capability of the Promise tx4000 and if we'd use software
raid instead, what would be the CPU overhead?

> 
> linux software raid hsa been as releiable as anything else we've used over 
> the years, the lack of reliabilitiy in your situation will come entirely 

Good to hear.

> from failing disks, lose one and your filesystem is toast.

I was aware of that, thanks!

> 
> joelja
> 
> On Sun, 28 Dec 2003, Johannes Ruscheinski wrote:
> 
> > Hi,
> > 
> > We're looking for a low-cost high-reliability IDE RAID solution that works well
> > with the 2.6.x series of kernels.  We have about 1 TB (8 disks) that we'd
> > like to access in a non-redundant raid mode.  Yes, I know, that lack of
> > redundancy and high reliability are contradictory.  Let's just say that
> > currently we lack the funding to do anything else but we may be able to obtain
> > more funding for our disk storage needs in the near future.
> > 
> 
> -- 
> -------------------------------------------------------------------------- 
> Joel Jaeggli  	       Unix Consulting 	       joelja@darkwing.uoregon.edu    
> GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2
> 

-- 
Johannes
--
Dr. Johannes Ruscheinski
EMail:    ruschein_AT_infomine.ucr.edu ***          Linux                  ***
Location: science library, room G40    *** The Choice Of A GNU Generation! ***
Phone:    (909) 787-2279

Outlook, n.:
        A virus delivery system with added email functionality.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Arjan van de Ven]

[-- Attachment #1: Type: text/plain, Size: 500 bytes --]

On Sun, 2003-12-28 at 22:35, Johannes Ruscheinski wrote:

> Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> hardware raid capability of the Promise tx4000 and if we'd use software
> raid instead, what would be the CPU overhead?

be careful, almost all ata raid controllers out there are *software
raid* hidden in a binary only driver. Also generally the on-disk format
of these is quite unfortionate resulting in slower access than linux
software raid can do...

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Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[bert hubert]

On Sun, Dec 28, 2003 at 01:35:35PM -0800, Johannes Ruscheinski wrote:

> Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> hardware raid capability of the Promise tx4000 and if we'd use software
> raid instead, what would be the CPU overhead?

For the cost differential between linux native RAID and an external device
of similar capabilities, outfit yourself with an additional CPU. I don't use
RAID5 a lot but to a modern CPU, checksumming dozens of megabytes/second is
child's play:

raid5: measuring checksumming speed
   8regs     :  1479.600 MB/sec
   32regs    :   744.400 MB/sec
   pIII_sse  :  1649.200 MB/sec
   pII_mmx   :  1806.000 MB/sec
   p5_mmx    :  1915.200 MB/sec
raid5: using function: pIII_sse (1649.200 MB/sec)

This is on a 800MHz Celeron, so a recent >2Ghz system will do lots better
still.

-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Johannes Ruscheinski]

Also sprach Arjan van de Ven:
> On Sun, 2003-12-28 at 22:35, Johannes Ruscheinski wrote:
> 
> > Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> > hardware raid capability of the Promise tx4000 and if we'd use software
> > raid instead, what would be the CPU overhead?
> 
> be careful, almost all ata raid controllers out there are *software
> raid* hidden in a binary only driver. Also generally the on-disk format

Binary-only drivers are quite unacceptable to me!

> of these is quite unfortionate resulting in slower access than linux
> software raid can do...

Thanks for the advice!

-- 
Johannes
--
Dr. Johannes Ruscheinski
EMail:    ruschein_AT_infomine.ucr.edu ***          Linux                  ***
Location: science library, room G40    *** The Choice Of A GNU Generation! ***
Phone:    (909) 787-2279

Outlook, n.:
        A virus delivery system with added email functionality.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[H. Peter Anvin]

Followup to:  <1072647938.10298.3.camel@laptop.fenrus.com>
By author:    Arjan van de Ven <arjanv@redhat.com>
In newsgroup: linux.dev.kernel
> 
> On Sun, 2003-12-28 at 22:35, Johannes Ruscheinski wrote:
> 
> > Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> > hardware raid capability of the Promise tx4000 and if we'd use software
> > raid instead, what would be the CPU overhead?
> 
> be careful, almost all ata raid controllers out there are *software
> raid* hidden in a binary only driver. Also generally the on-disk format
> of these is quite unfortionate resulting in slower access than linux
> software raid can do...
> 

Not to mention, well, *proprietary*.  Consider this: with Linux
swraid, you don't have to worry about your manufacturer discontinuing
your product or going out of business; as long as you can connect your
disks to a CPU using any kind of controller you can recover your
data.  If a proprietary RAID controller croaks, and you can't get
another one of the same brand/model, you might have no more data...

	-hpa

-- 
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If you send me mail in HTML format I will assume it's spam.
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Joel Jaeggli]

On Sun, 28 Dec 2003, Johannes Ruscheinski wrote:

> Also sprach Joel Jaeggli:
> > well if you currently have 1tb in 8 non-redundant drives then you using 
> > 160GB disks... no?
> > 
> > the biggest p-ata disks right now are ~320GB so you can do a ~1TB software 
> > raid 5 stripe on a single 4 port ata controller such as a promise tx4000 
> > using regular software raid rather than the promise raid. that would end 
> > up being fairly inexpensive and buy you more protection.
> 
> Fisrt of all: thanks for the advice Joel!  Two questions: why not use the
> hardware raid capability of the Promise tx4000 and if we'd use software

on the low-end promise controllers (ie everything but the sx4000 and
sx6000) it's not hardware raid, it's the driver doing raid in this case
the promise fastrack driver. among other things their driver doesn't do
raid 5, just 0 1 or 0+1. so software raid does raid 5 and more.

to quote the config_blk_dev_ataraid:

 CONFIG_BLK_DEV_ATARAID:                                                 
âSay Y or M if you have an IDE Raid controller and want linux            
âto use its softwareraid feature.  You must also select an               
 appropriate for your board low-level driver below.                      

âNote, that Linux does not use the Raid implementation in BIOS, and      
âthe main purpose for this feature is to retain compatibility and        
âdata integrity with other OS-es, using the same disk array. Linux       
âhas its own Raid drivers, which you should use if you need better       
âperformance.          

I've also had two if the higher-end promise sx6000's and the suffering I 
incurred making them work with the i2o drivers particularly when promise 
revised the bioses on those cards means I can't recomend them for much.
 
> raid instead, what would be the CPU overhead?

The linux software raid layer is actually faster under most circumstances
the hardware raid controllers, doing raid5. but since the promise can't
actually do that (raid 5) anyway it's hard to compare them directly. the
3ware cards in my experience result in lower cpu utilization for i/o but
there hardware tops out at 80-145MB/s depending on model and we have
software raid subsystems that go faster than that at the expense of some 
of the rather bountiful cpu we have in those boxes.

> > 
> > linux software raid hsa been as releiable as anything else we've used over 
> > the years, the lack of reliabilitiy in your situation will come entirely 
> 
> Good to hear.
> 
> > from failing disks, lose one and your filesystem is toast.
> 
> I was aware of that, thanks!
> 
> > 
> > joelja
> > 
> > On Sun, 28 Dec 2003, Johannes Ruscheinski wrote:
> > 
> > > Hi,
> > > 
> > > We're looking for a low-cost high-reliability IDE RAID solution that works well
> > > with the 2.6.x series of kernels.  We have about 1 TB (8 disks) that we'd
> > > like to access in a non-redundant raid mode.  Yes, I know, that lack of
> > > redundancy and high reliability are contradictory.  Let's just say that
> > > currently we lack the funding to do anything else but we may be able to obtain
> > > more funding for our disk storage needs in the near future.
> > > 
> > 
> > -- 
> > -------------------------------------------------------------------------- 
> > Joel Jaeggli  	       Unix Consulting 	       joelja@darkwing.uoregon.edu    
> > GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2
> > 
> 
> 

-- 
-------------------------------------------------------------------------- 
Joel Jaeggli  	       Unix Consulting 	       joelja@darkwing.uoregon.edu    
GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Wakko Warner]

> Not to mention, well, *proprietary*.  Consider this: with Linux
> swraid, you don't have to worry about your manufacturer discontinuing
> your product or going out of business; as long as you can connect your
> disks to a CPU using any kind of controller you can recover your
> data.  If a proprietary RAID controller croaks, and you can't get
> another one of the same brand/model, you might have no more data...

Speaking of which, since most DIE^WIDE RAID controllers are really software
driven, it may be possible to get the sw module to read the disks off of any
controller

My machine at work has an onboard promise raid controller but I run linux sw
raid0 on 2 of the disks (4 total, other 2 are not in a raid)

I'm not sure about real hardware raid.  Like the Mylex or Adaptec (SCSI)

-- 
 Lab tests show that use of micro$oft causes cancer in lab animals

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Samuel Flory]

Johannes Ruscheinski wrote:

> Hi,
> 
> We're looking for a low-cost high-reliability IDE RAID solution that works well
> with the 2.6.x series of kernels.  We have about 1 TB (8 disks) that we'd
> like to access in a non-redundant raid mode.  Yes, I know, that lack of
> redundancy and high reliability are contradictory.  Let's just say that
> currently we lack the funding to do anything else but we may be able to obtain
> more funding for our disk storage needs in the near future.


   It really depends on what you mean by low cost?  The ony ide raid 
controller that does 8 PATA drives well under linux is the 3ware 
controller.  For SATA drives you have the 3ware, and adaptec controller. 
    In theroy the highpoint 8 port sata card would be a good canidate 
for software raid, but highpoint has yet to cough up an open source 
drive yet.

   It you want to go the software raid route and have 2 spare pci solts. 
  You can go with either the high point rocket raid 454 (PATA), or the 
promise SATA150 TX4.

   I really don't recommend any of promise's cards that use use the i2o 
driver, or any sort of binary only driver.

PS- Why not at least run software raid 5?  It takes far less cpu than 
you'd think, and can save your ass.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Tomas Szepe]

On Dec-28 2003, Sun, 18:10 -0800
Samuel Flory <sflory@rackable.com> wrote:

> PS- Why not at least run software raid 5?  It takes far less cpu than 
> you'd think, and can save your ass.

Absolutely.  With eight low-cost IDE disks, you'd be nuts to go raid0
or linear.

-- 
Tomas Szepe <szepe@pinerecords.com>

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Johannes Ruscheinski]

Also sprach Tomas Szepe:
> On Dec-28 2003, Sun, 18:10 -0800
> Samuel Flory <sflory@rackable.com> wrote:
> 
> > PS- Why not at least run software raid 5?  It takes far less cpu than 
> > you'd think, and can save your ass.
> 
> Absolutely.  With eight low-cost IDE disks, you'd be nuts to go raid0
> or linear.
> 

I'll probably go with raid5 and the Promise tx4000 card recommended by Joel.
It looks like I'll have the funding to buy another box and another 1 TiB of
disk space.  Thanks for all the advice!!

> -- 
> Tomas Szepe <szepe@pinerecords.com>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
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-- 
Johannes
--
Dr. Johannes Ruscheinski
EMail:    ruschein_AT_infomine.ucr.edu ***          Linux                  ***
Location: science library, room G40    *** The Choice Of A GNU Generation! ***
Phone:    (909) 787-2279

Outlook, n.:
        A virus delivery system with added email functionality.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Samuel Flory]

Johannes Ruscheinski wrote:
> Also sprach Tomas Szepe:
> 
>>On Dec-28 2003, Sun, 18:10 -0800
>>Samuel Flory <sflory@rackable.com> wrote:
>>
>>
>>>PS- Why not at least run software raid 5?  It takes far less cpu than 
>>>you'd think, and can save your ass.
>>
>>Absolutely.  With eight low-cost IDE disks, you'd be nuts to go raid0
>>or linear.
>>
> 
> 
> I'll probably go with raid5 and the Promise tx4000 card recommended by Joel.
> It looks like I'll have the funding to buy another box and another 1 TiB of
> disk space.  Thanks for all the advice!!
> 
> 

   A word of advice when using software raid.  Be sure to run badblocks 
on all the disks before creating your array.  Software raid isn't as 
nice about bad sectors as most hardware raid controllers.  On the other 
hand the md driver kicks the ass of nearly every raid controller I've tried.

-- 
There is no such thing as obsolete hardware.
Merely hardware that other people don't want.
(The Second Rule of Hardware Acquisition)
Sam Flory  <sflory@rackable.com>

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Tomas Szepe]

On Dec-29 2003, Mon, 11:04 -0800
Samuel Flory <sflory@rackable.com> wrote:

>   A word of advice when using software raid.  Be sure to run badblocks 
> on all the disks before creating your array.  Software raid isn't as 
> nice about bad sectors as most hardware raid controllers.  On the other 

_initial_ bad sectors, that is.

> hand the md driver kicks the ass of nearly every raid controller I've tried.

word.

-- 
Tomas Szepe <szepe@pinerecords.com>

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Wakko Warner]

> nice about bad sectors as most hardware raid controllers.  On the other 
> hand the md driver kicks the ass of nearly every raid controller I've tried.

Faster than the mylex extreme raid 2000?  or one of the higher end adaptecs?

What's funny is I have a mylex dac960pdu with 4 disks in raid 5 being outran
by a single usb2.0 hard disk =)

(4.3gb st15150n fast wide in an alpha server 1000a)

-- 
 Lab tests show that use of micro$oft causes cancer in lab animals

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Tomas Szepe]

On Dec-29 2003, Mon, 19:03 -0500
Wakko Warner <wakko@animx.eu.org> wrote:

> > nice about bad sectors as most hardware raid controllers.  On the other 
> > hand the md driver kicks the ass of nearly every raid controller I've tried.
> 
> Faster than the mylex extreme raid 2000?  or one of the higher end adaptecs?

Even faster than HP/Compaq cciss hwraid setups, yes.

-- 
Tomas Szepe <szepe@pinerecords.com>

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Wakko Warner]

> > > nice about bad sectors as most hardware raid controllers.  On the other 
> > > hand the md driver kicks the ass of nearly every raid controller I've tried.
> > 
> > Faster than the mylex extreme raid 2000?  or one of the higher end adaptecs?
> 
> Even faster than HP/Compaq cciss hwraid setups, yes.

I've personally not had any experience with any hardware raid other than the
mylex DAC960 family.

One thing that keeps me from using the linux raid sw is the fact it can't be
partitioned.  I thought about lvm/evms, but I'm unwilling to make an initrd to
set it up (mounting root).  Unfortunately boot loaders don't seem to support
anything other than raid1. (Mostly lilo, but I'm not sure grub would do this
either)

-- 
 Lab tests show that use of micro$oft causes cancer in lab animals

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[Samuel Flory]

Wakko Warner wrote:
>>>>nice about bad sectors as most hardware raid controllers.  On the other 
>>>>hand the md driver kicks the ass of nearly every raid controller I've tried.
>>>
>>>Faster than the mylex extreme raid 2000?  or one of the higher end adaptecs?
>>
>>Even faster than HP/Compaq cciss hwraid setups, yes.
> 
> 
> I've personally not had any experience with any hardware raid other than the
> mylex DAC960 family.
>

   I know a number of people that run their mylex cards in jbod mode and 
use software raid;-)


> One thing that keeps me from using the linux raid sw is the fact it can't be
> partitioned.  

   You're thinking of it the wrong way.  You just create a bunch of 
partitions and make them into raid devices.  You shouldn't be using the 
entire disk or you will break autodetection.

> I thought about lvm/evms, but I'm unwilling to make an initrd to
> set it up (mounting root).  Unfortunately boot loaders don't seem to support
> anything other than raid1. (Mostly lilo, but I'm not sure grub would do this
> either)
> 

   Lilo deals well with raid 1 devices.  I typical create a small raid 1 
mirror as /boot.  Just be sure to install your bootloader on to all 
drives.  Newer versions of lilo will do the right thing if told to use 
/dev/mdwhatever.

-- 
There is no such thing as obsolete hardware.
Merely hardware that other people don't want.
(The Second Rule of Hardware Acquisition)
Sam Flory  <sflory@rackable.com>

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[bill davidsen]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 2900 bytes --]

In article <Pine.LNX.4.44.0312281516060.21070-100000@twin.uoregon.edu>,
Joel Jaeggli  <joelja@darkwing.uoregon.edu> wrote:

| on the low-end promise controllers (ie everything but the sx4000 and
| sx6000) it's not hardware raid, it's the driver doing raid in this case
| the promise fastrack driver. among other things their driver doesn't do
| raid 5, just 0 1 or 0+1. so software raid does raid 5 and more.
| 
| to quote the config_blk_dev_ataraid:
| 
|  CONFIG_BLK_DEV_ATARAID:                                                 
| âSay Y or M if you have an IDE Raid controller and want linux            
| âto use its softwareraid feature.  You must also select an               
|  appropriate for your board low-level driver below.                      
| 
| âNote, that Linux does not use the Raid implementation in BIOS, and      
| âthe main purpose for this feature is to retain compatibility and        
| âdata integrity with other OS-es, using the same disk array. Linux       
| âhas its own Raid drivers, which you should use if you need better       
| âperformance.          
| 
| I've also had two if the higher-end promise sx6000's and the suffering I 
| incurred making them work with the i2o drivers particularly when promise 
| revised the bioses on those cards means I can't recomend them for much.
|  
| > raid instead, what would be the CPU overhead?
| 
| The linux software raid layer is actually faster under most circumstances
| the hardware raid controllers, doing raid5. but since the promise can't
| actually do that (raid 5) anyway it's hard to compare them directly. the
| 3ware cards in my experience result in lower cpu utilization for i/o but
| there hardware tops out at 80-145MB/s depending on model and we have
| software raid subsystems that go faster than that at the expense of some 
| of the rather bountiful cpu we have in those boxes.

The problem with the Linux software RAID is that's in the kernel. So if
the boot disk dies you don't get to boot and use the kernel. With the
controller RAID you do use the the RAID-1 copy, and boot, and sometimes
that's the feature which counts more than all the rest.

Now if you run LinuxBIOS you CAN do this all yourself, but unless you do
there are still some reliability issues.

Also note that if you do mirroring you use twice as much disk buffer
space to queue two writes, which could impact the performance in a low
memory system. That's theory, I haven't benchmarked.

Promise used to make a little adaptor which did RAID-1 on two drives and
made them look like one. This was not at the controller as I recall, but
in the cable, where the data was split. That would give boot reliability
without losing a device pair, but I have no idea how well it worked
other than in a demonstration.
-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

Re: Best Low-cost IDE RAID Solution For 2.6.x? (OT?)

[bill davidsen]

In article <20031230094157.A7191@animx.eu.org>,
Wakko Warner  <wakko@animx.eu.org> wrote:
| > > > nice about bad sectors as most hardware raid controllers.  On the other 
| > > > hand the md driver kicks the ass of nearly every raid controller I've tried.
| > > 
| > > Faster than the mylex extreme raid 2000?  or one of the higher end adaptecs?
| > 
| > Even faster than HP/Compaq cciss hwraid setups, yes.
| 
| I've personally not had any experience with any hardware raid other than the
| mylex DAC960 family.
| 
| One thing that keeps me from using the linux raid sw is the fact it can't be
| partitioned.  I thought about lvm/evms, but I'm unwilling to make an initrd to
| set it up (mounting root).  Unfortunately boot loaders don't seem to support
| anything other than raid1. (Mostly lilo, but I'm not sure grub would do this
| either)

What? You do the RAID on partitions, so you can do anything you want.
They don't aven have to be the same type RAID, I once ran fours drives
with a small 0+1 partiton (2+2) for reliability and read performance,
and a large partition of the rest of the drives RAID-5. Different stripe
size, because one array had many small reads and the other many large
reads.

You can do anything you have the guts to do, except change partition
size once you are setup.
-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.