Date: Tue, 26 May 1998 12:11:17 -0400 (EDT) From: Charles Owens <owensc@enc.edu> To: Simon Shapiro <shimon@simon-shapiro.org> Cc: Raul Zighelboim <rzig@verio.net>, freebsd-scsi@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG, Tom <tom@sdf.com> Subject: RE: DPT install problem Message-ID: <Pine.BSF.3.95q.980526120346.26872B-100000@itsdsv2.enc.edu> In-Reply-To: <XFMail.980526125853.shimon@simon-shapiro.org>
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On Tue, 26 May 1998, Simon Shapiro wrote: > > 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. The setup I'm planning consists of 14 4.5GB UW (probably Seagate Cheetahs) drives split across two busses (using the DPT 3334UW/2). If you don't mind, could you comment a bit further as to what this tuning would entail in my case? The array will be at the heart of a file server cluster housing user and group home directories for 1300 or so users. Also, how much cache RAM on the controller is practically useful? Thanks, Charles > > > > ================================================== > > 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 > >> ---------------------------------------------------------------------- > >> --- > >> > >> > >> To Unsubscribe: send mail to majordomo@FreeBSD.org > >> with "unsubscribe freebsd-scsi" in the body of the message > > --- > > > Sincerely Yours, > > Simon Shapiro Shimon@Simon-Shapiro.ORG > 770.265.7340 > --- ------------------------------------------------------------------------- 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 ------------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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