On the readlink example, the "$" indicates a variable. So in a script you
could set vdev='015f' and then reference that value as ${vdev}. Or you could
just hard code in the "015f"....also note that the by-path disk nodes always zero-pad the beginning of a virtual device number, so it'll be four characters in length. It's stripping out the "1" in "$15f" because it's assuming you mean $1 as a variable, and (since you never initialized a $1 or passed it in as an argument/parameter) interpreting it as an empty string. If your script is always dealing with the same virtual device numbers, though, and not dealing with something that *has* to use the dasd* format, you may as well just hard-code the by-path name of the disk. You can find other mounts by /dev/dasd* in your scripts by running a grep through them, if that's a concern. Unlike network interfaces (which have a configurable persistent mapping in /etc/udev/rules.d/70-persistent-net.rules), there is not any way I'm aware of to force the assignment of a virtual disk to a particular "letter" in the /dev/dasd* scheme. Those assignments happen to usually remain stable - but, as you've seen, they can change if something changes the order in which they are brought on line. On Thu, Sep 29, 2011 at 12:59 PM, Ron Foster at Baldor-IS < [email protected]> wrote: > Peter, > We do not have SLES11, but from the manual, on page 21 (Module parameters > on the kernel parameter line), it appears that the appropriate format of > the dasd= parameter might be: > > dasd_mod.dasd=0.0.150-0.0.15f > > so your parameter line would be: > > parameters = "root=/dev/disk/by-path/ccw-0.0.0150-part1 > dasd_mod.dasd=0.0.150-0.0.15f > TERM=dumb" > > Ron Foster > > > ________________________________________ > From: Linux on 390 Port [[email protected]] On Behalf Of Peter E. > Abresch Jr. - at Pepco [[email protected]] > Sent: Thursday, September 29, 2011 11:09 AM > To: [email protected] > Subject: Re: DASD assignment different between SLES10 and SLES11 > > Yes, our root is always dasda and our swap is always dasdp. This is what > our original automated Linux cloning process expects and we wish to not > re-engineer our cloning process at this time. > > Under SLES10, in /etc/zipl.conf we have the following: > > parameters = "root=/dev/dasda1 dasd=150-15f TERM=dumb" > > Under SLES11, in /etc/zipl.conf we have the following: > > parameters = "root=/dev/disk/by-path/ccw-0.0.0150-part1 TERM=dumb" > > I am thinking this is where I need to make my change, but my own memory is > slow to swap back in for me to remember all of it. > > But . . . > > readlink -f /dev/disk/by-path/ccw-0.0.$15F > reveals /dev/disk/by-path/ccw-0.0.5F - it seems to strip the 1 from the > 15f. > > In my SLES10 cloning script, where I have the following: > > echo "Creating DASD swap space on /dev/dasdp1" > swapoff -a > echo "Formatting DASD swap space on /dev/dasdp1" > dasdfmt -vy -f /dev/dasdp -d cdl -l swap01 -b 4096 > echo "Partitioning DASD swap space on /dev/dasdp1" > fdasd -l swap01 -a /dev/dasdp > echo "Making DASD swap space on /dev/dasdp1" > sleep 5 > mkswap /dev/dasdp1 > echo "Activating DASD swap space on /dev/dasdp1" > swapon -a > echo "Verifying DASD swap space on /dev/dasdp1" > swapon ?s > > I can change in my SLES11 cloning script to: > > echo "Creating DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > swapoff -a > echo "Formatting DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > dasdfmt -vy -f /dev/disk/by-path/ccw-0.0.5F -d cdl -l swap01 -b 4096 > echo "Partitioning DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > fdasd -l swap01 -a /dev/disk/by-path/ccw-0.0.5F > echo "Making DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > sleep 5 > mkswap /dev/disk/by-path/ccw-0.0.5F > echo "Activating DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > swapon -a > echo "Verifying DASD swap space on /dev/disk/by-path/ccw-0.0.5F" > swapon ?s > > Is this what I should do? I am hesitant as there might me other scripted > mounts that do /dev/dasdx# . Should I eat the bullet now or defer? > > > > Peter > > > > From: Ron Foster at Baldor-IS <[email protected]> > To: [email protected] > Date: 09/29/2011 11:38 AM > Subject: Re: DASD assignment different between SLES10 and SLES11 > Sent by: Linux on 390 Port <[email protected]> > > > > Peter, > > Actually we observed this behavior as far back as SLES10 SP3. We started > using persistent device names and forgot about it. > > The documentation for this is in the release notes. From the release > notes: > > Installation using Persistent Device names > If you plan to add additional storage devices to your system after the > OS > installation, we strongly recommend to use persistent device names for > all > storage devices during installation. The installer by default uses the > kernel device names. > > There is additional information in the SLES11 device driver manual on the > developerworks site. > From the Device Drivers, Features, and Commands manual > SC34-2595-01 > > (from page 35) > autodetect > causes the DASD device driver to allocate device names and the > corresponding minor numbers to all DASD devices and set them online > during the boot process. See ?DASD naming scheme? on page 31 for the > naming scheme. > The device names are assigned in order of ascending subchannel numbers. > Auto-detection can yield confusing results if you change your I/O > configuration and reboot, or if you are running as a guest operating > system > in VM because the devices might appear with different names and minor > numbers after rebooting. > > What may have changed is how dasd= is specified and/or how it works. It > is different between the SLES10 and SLES11 manuals. > > Ron Foster > > > > > ________________________________________ > From: Linux on 390 Port [[email protected]] On Behalf Of Peter E. > Abresch Jr. - at Pepco [[email protected]] > Sent: Thursday, September 29, 2011 9:59 AM > To: [email protected] > Subject: DASD assignment different between SLES10 and SLES11 > > Under SLES10, we see the following: > > 0.0.0150(ECKD) at ( 94: 0) is dasda : active at blocksize 4096, > 600840 blocks, 2347 MB > 0.0.0151(ECKD) at ( 94: 4) is dasdb : active at blocksize 4096, > 600840 blocks, 2347 MB > 0.0.0152(ECKD) at ( 94: 8) is dasdc : active at blocksize 4096, > 600840 blocks, 2347 MB > 0.0.0153(ECKD) at ( 94: 12) is dasdd : active at blocksize 4096, > 600840 blocks, 2347 MB > 0.0.0154(ECKD) at ( 94: 16) is dasde : active at blocksize 4096, > 600840 blocks, 2347 MB > 0.0.015f(ECKD) at ( 94: 60) is dasdp : active at blocksize 4096, > 150840 blocks, 589 MB > > Notice that 0.0.015f is dasdp > > > Under SLES11, we see the following: > > Bus-ID Status Name Device Type BlkSz Size Blocks > > ============================================================================== > 0.0.0150 active dasda 94:0 ECKD 4096 2347MB 600840 > 0.0.0151 active dasdb 94:4 ECKD 4096 2347MB 600840 > 0.0.0152 active dasdc 94:8 ECKD 4096 2347MB 600840 > 0.0.0155 active dasdd 94:12 ECKD 4096 2347MB 600840 > 0.0.0156 active dasde 94:16 ECKD 4096 2347MB 600840 > 0.0.015f active dasdf 94:20 ECKD 4096 589MB 150840 > > Notice that 0.0.015f is dasdf rather than dasdp. How can I insure that > 0.0.015f is always dasdp? > > I read that this behavior had change but naturally now that I need this > doc, I cannot find it anywhere. I do not remember where I read it. Errrr. > > Can anyone point me in the right direction? Thanks as always. > > Peter > > This Email message and any attachment may contain information that is > proprietary, legally privileged, confidential and/or subject to copyright > belonging to Pepco Holdings, Inc. or its affiliates ("PHI"). This Email > is > intended solely for the use of the person(s) to which it is addressed. If > you are not an intended recipient, or the employee or agent responsible > for > delivery of this Email to the intended recipient(s), you are hereby > notified > that any dissemination, distribution or copying of this Email is strictly > prohibited. If you have received this message in error, please > immediately > notify the sender and permanently delete this Email and any copies. 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