Date: Thu, 2 Sep 1999 09:54:40 -0600 (MDT) From: "Justin T. Gibbs" <gibbs@narnia.plutotech.com> To: Tony Holmes <tony@crosswinds.net> Cc: scsi@FreeBSD.org Subject: Re: Binding host channels Message-ID: <199909021554.JAA72708@narnia.plutotech.com> In-Reply-To: <19990902090111.A17707@crosswinds.net>
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In article <19990902090111.A17707@crosswinds.net> you wrote: > I am currently in the process of upgrading a set of servers here and, > after a lot of reading and thought, have decided upon a CMD SCSI > controller system. I require huge volumes of disk with moderately > decent throughput, so a CMD 5500 controller with 4 host and 5 SCSI > disk channels was selected. CMD controllers have been known to deal poorly with resource shortages when attached to multiple hosts. Perhaps they have addressed this issue, but I haven't heard any reports that they have. The CMD also has a fairly low transaction capability (32?), so I wouldn't recommend them for data sets comprised of lots of small files (e.g. news). > 4 * U2W 5 * U2W > |-----------| CMD |----------| > FreeBSD |-----------| 5500 |----------| Lot's O Disk > Server |-----------| |----------| > |-----------| |----------| > |----------| > > My question is this: Is it possible to "bind" the four host channels > together to make the system appear to have one, very fast host channel > connected to one very large disk (ala the CMD)? Or do I have to result > to partitioning the disks into 4 logical units on the controller? What you want is multi-pathing to a single device and no, it isn't currently supported. I am interested in supporting it, but have limited free time right now. I might be able to free up contracting time to do the work if it is really important to you. > The application (massive web space, with no limits per account) pushes for > a single volume that can grow over time. Our FFS can't be grown dynamically. It could be modified to allow this, but you'd need to contract an FS guru to do the work. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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