Re: SCSI disk devices

eyal (eyal@eyal.emu.id.au)
Sun, 04 May 1997 10:12:36 +1000


Eric Youngdale wrote:

> Let me pose the question again. For large numbers of disks (you get
> to define large), is scsidev an adequate solution to the problem or not?

The problem is one of convinience. Whenever one installs a new device
there
is a big hassle. It comes in two forms:

1) The SCSIIDs remain the same, but the Linux logical names change due
to
the current name assignment rules. This can be easily fixed by using
id based names.

2) One actually changes the ids. We now need a way to identify the
devices
in an independent manner (using device name, serial#, whatever).

If you have multiple controllers than the problem is again complicated.

So, I want a scsidev kind of solution. The exact form of the generated
name
is really not than critical as long as it is stable. I will continue to
use my own links in /dev for devices that I use often manually.

Tell you what. Here is how I once handles peoples sensibilities in
naming
floppies (a program would write and label them). I allowd a string
parameter with embedded escapes for the special identifiers. This way
your
name is:
"s%th%d-%ac%ci%il%lp%p"

%t type
%d driver
%a I/O address
%c channel
%i scsi id
%l scsi lun
%p partition

Any good? Only problem is you always get this final "p0" even for
devices
with no partitions, but I am sure you can think up a solution if it
eally
bothers someone.

In other words, I suggest you put the naming argument back in the users
court.

--
Eyal Lebedinsky		(eyal@eyal.emu.id.au)