Date: Mon, 26 Oct 1998 19:35:56 +0100 (CET) From: Wilko Bulte <wilko@yedi.iaf.nl> To: peter@taronga.com (Peter da Silva) Cc: scsi@FreeBSD.ORG Subject: Re: Do we support > 32 drives yet? Message-ID: <199810261835.TAA13230@yedi.iaf.nl> In-Reply-To: <199810261709.LAA29710@bonkers.taronga.com> from Peter da Silva at "Oct 26, 98 11:09:35 am"
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As Peter da Silva wrote... > > >/* > > 3 2 1 0 > > 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 > > _________________________________________________________________ > > | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | > > ----------------------------------------------------------------- > > | TYPE |UNIT_2 | SLICE | MAJOR? | UNIT |PART | > > ----------------------------------------------------------------- > >*/ > > Other than hardcoding device numbers in the config file, is there any way of > tying a device to a particular bus/target/lun combination the way you can > in Digital UNIX and in System-V derived systems where this data is encoded > into the minor number? This seems to be a requirement if you want to be > able to hot-add drives. For example, I can plug a drive into a Storageworks > shelf on my DU box, and calculate the minor number for it from the bus, > target, and LUN (bus*K1+target*K2+lun)... on FreeBSD I'd have to prebuild > a kernel or preallocate a bunch of unused minors. > > With an HSZ50 I can stick 12 shelves of drives on a single controller, for > 84 drives per controller. We run these in JBOD mode because each project wants ??? The HSZ50 backend is not wide scsi. In a BA355 type enclosure you can have 24 disks, using BA35[06] device shelves you can have 6 (backend channels) * 7 (disks per shelf) is 42 disks. Using redundant power supplies in your BA35[06] you are limited to 6 * 6 = 36 disks. I don't see how you get to 84 disks. > to be able to keep a couple of disks "on the shelf" if necessary, ready to > slot in so they can get to work on a problem on a few minutes notice. Why not run ADVFS on a big RAIDset (14 disks max)? ADVFS also gives you a lot of flexibility. You can have a max of 32 LUNs presented at the HSZ50s frontend bus (4 SCSI IDs * 8 LUNs). So full JBOD will not work with the max 36 disk config. > Digital UNIX has a terrific SCSI subsystem, but it looks like FreeBSD is > dogging its heels. This is one of the things keeping DU ahead. If you want to run the Altavista's of this planet you better have a good I/O subsys ;-) Wilko _ ______________________________________________________________________ | / o / / _ Bulte email: wilko@yedi.iaf.nl |/|/ / / /( (_) Arnhem, The Netherlands WWW : http://www.tcja.nl ______________________________________________ Powered by FreeBSD __________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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