Date: Wed, 21 Jan 1998 09:28:39 -0800 (PST) From: Simon Shapiro <shimon@simon-shapiro.org> To: Jaye Mathisen <mrcpu@cdsnet.net> Cc: freebsd-scsi@FreeBSD.ORG, salyzyn@dpt.com Subject: Re: RAID on FreeBSD Message-ID: <XFMail.980121092839.shimon@simon-shapiro.org> In-Reply-To: <Pine.NEB.3.95.980120185607.23979E-100000@mail.cdsnet.net>
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On 21-Jan-98 Jaye Mathisen wrote:
>
> While I realize this is an old message, it's answers like this that make
> me glad I keep on buying DPT.
>
> I appreciate DPT's efforts in making their board work with just about
> everything.
>
> On Fri, 12 Dec 1997, Mark Salyzyn wrote:
>
>> In article <3.0.32.19971211155601.0092e580@gw1.tesys.com>, you wrote:
>> >At 03:04 PM 12/11/97 -0800, Tom wrote:
>> >>On Thu, 11 Dec 1997, Wilko Bulte wrote:
>> >>> > 9 drives in an uncomfortable number for RAID5. Probably better
>> >>> > to go
>> >>> Why would 9 drives be uncomfartable?
>> >> Well, if you are going to making one arrray of 9 drives, write
>> >>performance will bad. If you are going to making 3 arrays of 3
>> >>drives each, you will end up with a lot of overhead.
>> >> RAID5 arrays of 5 drives is kinda of nice sweet spot. If you go
>> >> much
>> >>bigger, just use RAID0 over multiple RAID5.
>> >Please note that dual RAID support (dpt based) is not available under
>> >FreeBSD(there are few other OS's which do support it), as per my
>> >information.. Can someone verify that..
>>
>> Software RAID is not available for the current driver by Simon.
Hi Mark! This is true. Time, simply no time.
>> However, we have supplied Simon sources to a RAID-0 subsystem that he
>> may add to the driver in the future.
Once we get the multi-initiator code to work, we will look at the in-kernel
RAID-0.
>> There is nothing preventing an OS RAID-0 from being set up, the
>> only disadvantages are that it is not integrated into the DPT management
>> solutions and you can not boot off of a dual level RAID device utilizing
>> the second level within an OS driver.
While I totally agree that an integrated solution is better, the ccd driver
in FreeBSD does a fine job for most. The only thing it does not do is
allow you to boot from a RAID-0 conposed of several RAID-{1,5}.
And yes, Unlike some other HBA manufacturers, DPT actually helps and
encourages use of its products in a non-M$ non-NDA environment.
----------
Sincerely Yours,
Simon Shapiro
Shimon@Simon-Shapiro.ORG Voice: 503.799.2313
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