[WBEL-users] LSI SATA 150-6 [Update: LSI SATA 150-2]

[Namdar Bolour]

Nick:

Yes, Nick, you're right about the 2-channel version of this card.  It is 
a -software- RAID card, not hardware like the 4- and 6-channel versions, 
as I confirmed by a recent call to LSI.  This means the RAID processing 
(striping, mirroring, or RAID5 parity calculations) is done on the host 
at the driver level, not on a specialized processor on the card, which 
might explain the slow performance.

However, RAID1 in software should not use that much CPU power, since 
it's just moving data, not calculating parity as in RAID5 (a rebuild is 
different, of course, since it has to replicate the whole disk).  To be 
more specific, there is a slight speed penalty when -writing- to RAID1, 
since it has to write twice, but on -reads- it can be faster if the 
dirver is designed to read from both drives in the mirror simultaneously 
(actually, interleave the reads), so your performance under normal 
conditions (not rebuilding) may not be that bad.  (These are general 
statements about RAID, as I have not played with software RAID on linux, 
only on Solaris).

God bless the marketers - they used the same series name (Megaraid SATA 
150-x) for the cheapie card!  When I can't tell from the specs whether a 
RAID card is hardware or software, I look at a picture of the card (a 
great source of pictures is www.newegg.com):  if it has just one or two 
chips, it's software RAID.  If it has lots of chips or a big processor 
with a heat sink, etc, it's probably hardware RAID.  Another clue is 
whether it does RAID5, which is the most computation-intensive of the 
RAID levels, and doing it in software would slow down the host too 
much.  You'll notice the -2 can't do RAID5.  The price of the -2 also 
gives it away - only $75 vs $250 for the -4!

Don't mean to rub in your bad experience, just thought this would help 
the community.

-- Nam

Nick Bright wrote:

> I was so impressed with my LSI SATA 150-6, when the time came to 
> purchase a 2ch RAID controller for a simple mirroring scenario, I was 
> gung-ho to purchase the 2 channel version of this card. However, I 
> have discovered that this card has some problems. Thought I would 
> share with the list to prevent anyone from making the same mistake.
>
> 1) This is NOT a 2 channel version of the 150-4 or 150-6 (which are 
> the same thing, essentially).
> 2) Under WBEL it simply shows up as two SATA drives (even though I 
> configured it as a mirror in the firmware)
> 3) There is no driver for recent *nixes. It does NOT USE THE MEGARAID 
> DRIVER. Repeat does NOT use megaraid.o as the product name would 
> imply. This is not a MEGARAID card.
> 4) SLLLLLLOOOOOOWWWWWWWWW. It took *18* hours to build a simple mirror 
> of two 80Gb drives. Yes, 18. Not 8. 18.
>
> I can not reccomend this product to anyone. Lack of drivers, plus 
> horrible performance make me say that this product is crap.
>
> Oh yes, I also tried to install windows on it for giggles & grins. 
> Windows (after F6'ing to install the correct driver) never could find 
> a drive.
>
> Hoffmann, Tony wrote:
>
>> I would agree with this evaluation.  we've been seeing at least 
>> 30MB/s write
>> and
>> 50MB/s read in a raid5 config with write-back and adaptive readahead
>> activated.
>> We have plugged in a 64bit/66MHz slot on a mainboard from Supermicro.
>>
>> My only complaint is no individual headers for disk activity LEDs.
>>
>> Tony
>>
>> -----Original Message-----
>> From: whitebox-users-admin@beau.org
>> [mailto:whitebox-users-admin@beau.org]On Behalf Of Nick Bright
>> Sent: Thursday, November 18, 2004 7:11 PM
>> To: Aly Dharshi
>> Cc: whitebox-users@beau.org
>> Subject: Re: [WBEL-users] LSI SATA 150-6
>>
>>
>> The card works excellently, with the stock megaraid.o driver that 
>> every other MegaRAID product uses. I am quite satisified with 
>> performance and compability. As well, the acompanying management 
>> software is pretty good. Two thumbs up for this card.
>>
>> My test of the card was in my Del 1600SC (dual Xeon 2Ghz, 2Gb RAM) in 
>> a PCI-X slot
>> I used six Seagate 80GB drives (Model ST380013AS)
>>
>> In RAID 5, DirectIO caching, & Adaptive Read ahead the performance 
>> was a bit better than a single IBM UltraStar 18Gb 10,000 RPM Ultra 
>> 160 drive.
>>
>> I can post some bonnie++ benchmark results if there is interest.
>>
>> Sustained writes of a 4Gb file (at 1Mb and 4Kb block sizes) resulted 
>> in 35Mb/sec write speeds.
>>
>> time dd if=/dev/zero of=testfile bs=4k count=1048576
>> and
>> time dd if=/dev/zero of=testfile bs=1024k count=4096
>>
>> were used to attain that result.
>>
>>
>> - Nick
>>
>> Aly Dharshi wrote:
>>
>>  
>>
>>> No clue, but do let us know of your results, maybe I can be 
>>> persuaded to by it :)
>>>
>>> Cheers,
>>>
>>>    Aly.
>>>
>>> Nick Bright wrote:
>>>
>>>   
>>>
>>>> I'm buying an LSI SATA 150-6 (6 channel sata raid), and was 
>>>> wondering if
>>>> anyone had tried using one of these with whitebox? I know it's
>>>> supported, but I was wondering what someones results of actually using
>>>> it are?
>>>>
>>>>
>>>>     
>>>
>>
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>
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