Downloaded complete install DVD ISO fir 6.4 and burned to USB (as per instructions for 7.1). No DVD drive on this server.

Boots ok, asks me for location (no option for USB so I select hard drive), so I select /dev/sda. Goes though location, hostname etc but then fails with error

"The installer has tried to mount image #1 but cannot find it on the hard drive. Please copy this image to the drive and click retry".

Is it even possible to install 6.4 this way from USB?

Or is it best if I get portable DVD drive put image on there, boot from usb (as I've done) but select DVD drive as install?

/dev/sda is usually the primary disk drive on the machine. On a machine with 1 HDD, your USB drive would be /dev/sdb. You can leave the "directory" field blank.

Ah. There are two drives on the server. Would usb always be the last one?

Pretty sure it asks you which disk at the beginning. And only proceeds if /sda is selected.

If there are two HDDs in the server, the USB drive would probably be "sdc". The way I did it was to partition the USB flash drive and "dd" the ISO image to partition 1. On my laptop (with 1 internal drive), I select "sdb1" from the list, and the installer starts. (Partition 2 holds my kickstart files.)

before you get TOO FAR
6.4 is TWO versions and 2.5 YEARS out of date

6.6 is the current in the older 6 series and 6.7 is in testing

unless you are PAYING redhat a boatload of EXTRA CASH to lock in at 6.4
then use the current 6.6


also the RHEL6 instructions WILL BE DIFFERENT than 7.1's instructions

there are MAJOR changes to how the os works in the new 7 series

so
for 6 series USE THE 6 INSTRUCTIONS


also is this server a RAID set up ?
you will need the extra driver from redhat
so contact your tech support from redhat -- you do have the REQUIRED support contract ?
you will need it to get the driver