SGI's are usually easy to add disks to, whether they're external disks or internal disks.  Most of the time, these are SCSI disks.  This page will assume a SCSI option disk formatted for an SGI.  Instructions for adding the actual disk hardware are in your SGI's user manual.  However, there are a couple things you need to keep in mind with SCSI disks:

• While you can mix wide/narrow and SCSI version 1, 2, and 3 external disks provided you have the right cables/adapters, the SCSI controller will slow-down to the least common denominator among your disks.  So, if you have a SCSI I disk, the bus will be as fast as if all disks on the bus were SCSI I disks
• There are important cable length restrictions on external SCSI disks.  The bus will not function properly if these aren't kept.
• Do not mix differential SCSI and single-ended SCSI.  Most disks I've seen are single-ended.  Differential was designed to give longer cable lengths.  They are like oil and water.
• It's important to make sure the SCSI id on the disk you're adding is unique for the SCSI bus you're using.  If not, the bus won't function.
• Beware of Zip disks and Jazz disks.  While IRIX now supports them, they can be tricky from a hardware perspective.

    After you've added the disk and re-booted the system, you're ready to begin this step.  The IRIX 6.5 System Manager has a disk adding utility that makes this easy to do, and appears idiot-proof.
 

1. Determine the SCSI bus and the disk's unique ID
2. Enter "fx" and enter the SCSI bus and disk's unique ID.  Be careful with fx!
3. Go to "label" -> "show" ->  "all"; This should list all the information on the disk header about the disk as well as the partitions.  It's wise to write this down, in case of a disk crash.
4. If you're satisfied with this then hit ".." to go up the menu's until you have the option to exit.
5. Now you're ready to make a filesystem.  First, determine the device file for the partition.  It should be partition 7, so enter"mkfs_xfs /dev/dsk/dksXdYs7" making sure to replace X with the SCSI bus number and Y with the unique SCSI id number.
6. This should output some messages about the filesystem and indicate that it was done successfully.
7. Now you need to mount the filesystem that was on the partition to use it.  Choose a mount point which is simply a directory name on your main system disk that isn't already being used as a mount point by another filesystem.(use df to show where eash is mounted.) Create this directory with "mkdir -p full_directory_pathname".
8. Edit /etc/fstab and add the following string on a line of its own: "/dev/dsk/dksXdYs7    /mount-point     xfs   r w 0 0"
9. Save fstab and exit.  Now enter "mount -a" and "df".  You should see your new disk mounted and ready to use.  Change directories to it and make sure the permissions are right.  The disk will now re-mount automatically when the system is re-booted, and you're done!

last updated 2/28/00 by Martin McCormick, martinm@sas.upenn.edu