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Date:      Fri, 19 Jun 1998 20:47:40 -0400 (EDT)
From:      alex@nac.net
To:        Simon Shapiro <shimon@simon-shapiro.org>
Cc:        Chris Parry <laotzu@juniper.net>, freebsd-questions@FreeBSD.ORG, freebsd-SCSI@FreeBSD.ORG
Subject:   RE: DPT support binaries - How to Setup
Message-ID:  <Pine.BSF.3.96.980619203317.24846M-100000@iago.nac.net>
In-Reply-To: <XFMail.980619154837.shimon@simon-shapiro.org>

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Just some notes...


> The DPT controller creates and manages RAID array in a manner totally
> transparent to the (ANY) operating system.  Say, you have 45 disk drives,

ANY operating system that has a drive for the SCSI card. Like, remember
the FreeBSD didn't have a driver for it until recently.

>    1   RAID-0 array to be used for swap, /tmp, /var/tmp, /usr/obj, etc.
>        RAID-0 is very fast, but if any disk in the array fails, the whole
>        array will lose its data.  For the indicated use, this is acceptable
>        to us (Remember, this is just an example).
>        We do not need an awful lot of space, but we need the speed of at
>        least 15MB/Sec, so we will use 6 drives here.

Is this bright? Couldn't this panic the system in an event of a failure?


>    1   Huge RAID-0 array to contain news articles.  Again, we do not care if
>        we loose the article.  This array needs to be big and as fast as
>        possible.  We will use 33 disk drives here.

Also, I think this is a bad idea; at least make three 11-drive arrays
(RAID-0 is ok, but this way if you lose *1* disk, you don't lose the
ENTIRE spool, only a third -- and, you lose no storage space). With news
servers like breeze, this is very easy.


>    1   Huge RAID-5 array to contain our E-mail.  We need reliability and
>        capacity, so we will use 33 drives here.  In reality, RAID-5 arrays
>        are not so effective at this size, but this is just an exadurated
>        example.

You are putting news and mail on the same machine?


> What does the DPT do in case of disk failure?  

Usually kernel panic on bootup, but thats irrelevant.


> Typically, the user who buys a $3,000.00 disk controller, attaching it to

The most expensive 3334/UDW is like $1800.


> 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
                  Atheism is a non-prophet organization.
			 I route, therefore I am.
       Alex Rubenstein, alex@nac.net, KC2BUO, ISP/C Charter Member
               Father of the Network and Head Bottle-Washer
     Net Access Corporation, 9 Mt. Pleasant Tpk., Denville, NJ 07834
 Don't choose a spineless ISP! We have more backbone!  http://www.nac.net
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