Date: Tue, 26 May 1998 12:58:53 -0400 (EDT) From: Simon Shapiro <shimon@simon-shapiro.org> To: Raul Zighelboim <rzig@verio.net> Cc: freebsd-scsi@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG, Tom <tom@sdf.com>, Charles Owens <owensc@enc.edu> Subject: RE: DPT install problem Message-ID: <XFMail.980526125853.shimon@simon-shapiro.org> In-Reply-To: <A03CD00C69B1D01195AB00A024ECEB1691F109@kaori.communique.net>
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On 22-May-98 Raul Zighelboim wrote:
>
> My 0.02 cents:
> I did not installed FreeBSd on a DPT controller, but with an
> Adaptec controller. Nevertheless, I have a DPT controller on a system
> with a large fs (71780140 1K blocks). The system works, works well and
> has been up for 4 days as a very busy usenet news spool directory.
> This is running 2.2-RELENG from last sunday.
This confirms my observations. Thanx.
> As a sidebar; the DOS configuration software can only create arrays with
> up to 1 mbyte interleave. Is this a limitation on the hardware or the
> software ? Is (will there be) a way to create an array with a larger
> interleave (32 megs comes to mind).
An interleave factor larger than 1MB will be very inefficient:
a. The SCSI bus will be used (locked) for long periods. This will
cause poor multi-tasking response.
b. The cache memory will be able to contain very few stripes.
Also notice that in the context of FreeBSD, anything larger than 64K is
sort of mute, as the O/S limits all SCSI transfers to that size. I do not
know yet how CAM will do, but suspect it to be the same.
Ideally, stripe size should be such that the latency in setting up a
transfer + the latency in completeing a DPT-Host transfer are about equal
to the time to transfer one block (the reality is a bit more complex than
that); In this manner, the DPT can continue to ``feed'' blocks to the
system (or the other way around) without pausing for disk. This is why a
multiple-bus equipped DPT can achive transfer rates that are limited by the
PCI bus and/or the O/S. This takes some careful tuning and experimentation.
> Thanks, Simon, for a job well done.
Thanx. I am going to get started on CAM port in the next few days.
>
> ==================================================
> Raul Zighelboim rzig@verio.net
>
>> -----Original Message-----
>> From: Charles Owens [SMTP:owensc@enc.edu]
>> Sent: Friday, May 22, 1998 2:43 PM
>> To: Simon Shapiro
>> Cc: Tom; freebsd-stable@FreeBSD.ORG; freebsd-scsi@FreeBSD.ORG
>> Subject: RE: DPT install problem
>>
>> On Fri, 22 May 1998, Simon Shapiro wrote:
>>
>> >
>> > On 21-May-98 Tom wrote:
>> > >
>> > > I'm trying to use the boot-dpt 2.2.6-RELEASE floppy to bootstrap
>> a new
>> > > DPT based system. However, sysinstall hangs after newfs'ing the
>> > > filesystems.
>> > >
>> > > I'm using a 21GB array, with auto-defaults for the filesystems,
>> so /usr
>> > > is over 20GB in size. If I delete /usr and replace it with a
>> 500MB
>> > > filesystem, leaving the remaining space unallocated, sysinstall
>> has no
>> > > problem completing the newfs step.
>> > >
>> > > Anyone else had problems with sysinstall on a mid-sized array
>> like
>> > > this?
>> >
>> > Yup. Me :-)
>> > But not on 3.0-current. I noticed that 2.2 does not like huge
>> partitions,
>> > but this is not consnstent.
>> >
>> > Simon
>>
>> This has me a bit nervous. This July I will be implementing an NFS
>> server
>> with a 60GB DTP-based array. My plan has been to use 2.2-stable...
>> but
>> perhaps 3.0-current is my only choice? Is this -stable problem
>> understood, with a fix coming any time soon?
>>
>> Any other concerns that I should be sweating about as I'm planning on
>> building an array of this size? (and it will probably double in size
>> the
>> following summer)
>>
>> Thanks,
>> ---
>> ----------------------------------------------------------------------
>> ---
>> Charles N. Owens Email:
>> owensc@enc.edu
>>
>> http://www.enc.edu/~owensc
>> Network & Systems Administrator
>> Information Technology Services "Outside of a dog, a book is a
>> man's
>> Eastern Nazarene College best friend. Inside of a dog it's
>> too dark to read." - Groucho Marx
>> ----------------------------------------------------------------------
>> ---
>>
>>
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---
Sincerely Yours,
Simon Shapiro Shimon@Simon-Shapiro.ORG
770.265.7340
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