I'm trying to create a disaster recovery for my servers, all i need is to install a service on the server in able to connect the server to the tape library in case of a system failure for a system recovery, when using the linux rescue command from the installation cd, i don't know why i can't mount the usb disk (or probaby don't know how to), so any help on how to mount a usb flash disk while on linux rescue mode (or linux rescue nomount mode)

regards,

what are the commands you are trying(to give me a better idea of what your trying to do)

i'm trying to install a Disk Agent on the server so it will talk to the tape library server, this installation is necessary in case of system die. usually when i add my usb i find an entry for it in the /dev folder
but here

I think the problem is more to do with the age of the kernel in the rescue disk.

A modern kernel scans the USb ports regularly in the same way as a M$ system would do and so should allow a user to mount the SUB device, almost as soon as one is inserted.

My approach is issue this command before and after the USB device is inserted
I find newer Linux will add the new device and mount it as soon as I have inserted the USB device (like Ubuntu).

For what you are doing a Linux Live CD should do just the same thing. The rescue mode amounts to giving you just a kernel possible the exact one as the installed Linux but in usage any kernel will do. A newer kernel may even be more capable in dealing with the hardware.

ok, the usb part worked for me, but i'm stuck in another place so the usb solution is not applicable anymore, can anyone plz tell me how can i make a small os with some services installed and put it on a cd?

There is a Linux terminal command called "mkisofs" with which you can turn a root filing system into an iso that can be burn into a CD or DVD.

Some simple steps of how to use it is available in Chapter 3.4 of Grub Manual for burning just one Grub file into a CD.

It may be relevant to read this thread in which I burn DSL as one of the 7 distros into a rewritable DVD. The use mkisofs command is also provided in Step 5 of this thread.

To boot a CD one must use a special boot loader that can read iso9660 file format (El Torito bootable CD standard) from a CD or a DVD. This can be either Isolinux or Grub. My example is based on Grub which has a devoted file called stage2_eltorito to do just that.

Just checked my installed DSL V3.4 on 2.4.34 kernel with Grub 0.91. It has no stage2_eltorito so you must source this file from another distro. Grub 0.91 is oldest Grub I have come across. It is persisted by DSL because it probably has the smallest footprint. Current Grub is 0.97 and not many distros still use 2.4 kernels, as kernel 2.6.22 is now stable.

OK!linux rescue mode can mount usb devices. you can plug in USB storage disk before starting your server. the linux loader will be find usb storage device.enter the system.
type command:
#fdisk -l
if you find this message
/dev/sdaX "X maybe 0,1,2,3,etc"
this means usb module started,you can type command:
#mount /dev/sdaX /mnt/usb "Dont use -v fat parameter"