[rhn-users] max number of devices

[Corné Beerse]

alex wrote:
> 	Hello guys,
> 	I want to know how many sdx or hdx can we create on a redhat AS 2.1.
> 	Best Regards, Alex

I don't know details but see the system and what it has defined: `ls -l /dev/hd* 
` and `ls -l /dev/sd*`. The numbers at these devices are for partitions, the 
characters are for different devices.


/dev/hdx is for ide-disks. How many can you attach physically? Do you have some 
emulator or such using/needing more? Peek at the current defined /dev/hd* 
devices and peek at their major and minor numbers.

/dev/sd* is for scsi-disks. I have a iSCSI implementation here, that also uses 
/dev/sd* devices. Currently we are at /dev/sdi which works ok. The system goes 
beyond /dev/sdz with /dev/sdaa trough /dev/sdiv pre-configured.

Peeking at the major (8 and 65, 66, 67, 68, 69, 128, 129, 130, 131, 132, 133, 
134, 135) and minor (16 numbers per major) device numbers, I expect it can have 
14 * 16 == 224 devices.

If you definitly need to go beyond, peek if there are aditional major numbers 
which are free to use. Then use `mkdev` (see `man mkdev`) to define additional 
devices. (you might need to tweak/rebuild the kernel at this point...)



CBee