On mainframes - where ECKD DASD comes in smaller chunks then you might be used to (2.3 G for 3390-3, etc) -- using LVM (logical volume manager) is standard practice. While there is debate whether root should be in an LVM, or things should be separated out (/usr /tmp, etc) -- the essence is that can allow you to extend an existing filesystem by adding space to the logical volume manager - and then using it's commands (lvextend, et al) to extend existing/new logical volumes groups with this space. Without that ability, you'd run into problems when you have a filesystem fill up -- all you can do is copy it to a new, bigger space. 'logical volumes' let you extend a single filesystem across several physical volumes... things like striping can also come into play, but that's a more advanced topic... it's main use is to allow us to use these historically small DASD units to be used in multiples for a single filesystem (mount point, whatever).
LVM isn't a mainframe thing -- it's a Linux thing and there's lots of info on it via google, etc... Scott Rohling On Tue, Aug 11, 2015 at 12:49 PM, Howard V. Hardiman <hvhar...@ncat.edu> wrote: > Thanks. > > So here is my question. What is LVM and how do I know if I should be > using it? I did not use LVM on the install I am currently using. I > portioned the single dasd for 'swap' (384k) and '/' (7G). I did not use > LVM after that. > > I just now did a fresh install where I portioned the dasd the same way as > before, but I selected LVM and portioned that way. I suppose it worked. I > will retry the steps below to add additional dasd since they seem to be > geared towards LVM. > > I'm asking about LVM because based on the responses, it just seems that's > the easiest way to go... > > Comments? > > HH > > -----Original Message----- > From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of > Grzegorz Powiedziuk > Sent: Tuesday, August 11, 2015 12:27 PM > To: LINUX-390@VM.MARIST.EDU > Subject: Re: Adding DASD to a Debian guest > > It should be possible depending on what you did so far. > If your “/“ is on LVM then you should be able to add new dasd to it’s > volume group and extend the logical volume where “/“ lives. > > Make sure that when you restart linux, these dasd will automatically show > up in /proc/dasd/devices Stephen suggested over here creating these empty > files in /etc/sysconfig/hardware - I don’t know about that. I have never > done it this way (but I haven’t been using debian in many years and things > might have changed). As far as I remember, adding disks to zipl.conf and > running zipl command was sufficient. But I googled it and it seems like > that is something that came out with “wheeze debian” you might want to > follow that than. > > cd /etc/sysconfig/hardware > touch config-ccw-0.0.XXXX (0.0.0201 for example) > At this point it would be good to rebuild the initramfs > update-initramfs -uk $(uname -r) > Reboot and make sure new dasd are there (cat /proc/dasd/devices or lsdasd) > > Create new partition on every new disk > fdasd /dev/dasdc for example. And then “n” for new and follow instruction > to create a partition using all space on a device. > Now you should be able to create new physical volumes out of partitions > you’ve just created. > > pvcreate /dev/dasdc1 > > run pvscan to see if new pv is on the list > > Now you can extend the volume group. > Run vgdisplay to see what is the name of your current VG and then > > vgextend NAME_of_vg /dev/dasdc1 - this will add "physical volume” > dasdc1 on top of your current vg > > Now you should be able to extend the size of your root logical volume. > > Run lvdisplay to see what is the name of your root logical volume and then > > lvextend NAME_of_root_logical_volume /dev/dasdc1 - this will add free > space from dasdc1 on top of your root logical volume > > Now you should be able to extend size of your ext filesystem > > resize2fs NAME_of_root_logical_volume > > Repeat steps for every new dasd > > That should do it. In sles I was able to run resize2fs on a mounted root > filesystem, hopefully debian will be happy to do that as well. > > > Gregory Powiedziuk > > > > On Aug 10, 2015, at 8:07 PM, Howard V. Hardiman <hvhar...@ncat.edu> > wrote: > > > > Hello, > > > > I am also working on the system in question in the original question. > > > > I'm not used to creating or mounting the partitions using the command > line options. I do that during the install using the text gui. During > that process I partitioned the single dasd for just swap and / . I'd like > know what it takes to simply add more and 'tack it on to the end' of the > existing partition, if that's even possible. > > > > I am able to bring devices online and do the low level format and am > able to see the devices in /proc/dasd/devices... But, I could use more > detail after that. > > > > Thanks for any help you can provide. > > > > HH > > -----Original Message----- > > From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of > > Grzegorz Powiedziuk > > Sent: Thursday, August 6, 2015 3:16 PM > > To: LINUX-390@VM.MARIST.EDU > > Subject: Re: Adding DASD to a Debian guest > > > > Can you see them when you do > > cat /proc/dasd/devices ? > > If not than first bring them online (chccwdev -e 0.0.XXXX) and then > check again. > > If they are there, than you are ready to do a low level format with > dasdfmt /dev/dasdX (/proc/dasd/devices will tell you which dasdX is > that). > > After that, create partitions (or not if you don’t want to) with fdasd > /dev/dasdX Later you can create LVM (or not if you don’t want to) with > pvcreate, vgcreate, lvcreate. > > Last step is creating a filesystem with mkfs.ext4 (or ext3) on a new > partition or logical volume. And now, you can mount it. > > > > But you have to know that at this point you are also rewriting cylinder > 0 of this DASD (if it is really attached) so it’s label will change. > > > > > > Let us know if you need more details > > > > Grzegorz Powiedziuk > > > > > > > >> On Aug 6, 2015, at 3:04 PM, Cameron Seay <cws...@gmail.com> wrote: > >> > >> of course Debian can't see it until it's in a Linux filesystem. We > >> don't know how to format it while in Debian. > > > > > > ---------------------------------------------------------------------- > > For LINUX-390 subscribe / signoff / archive access instructions, send > > email to lists...@vm.marist.edu with the message: INFO LINUX-390 or > > visit > > http://www.marist.edu/htbin/wlvindex?LINUX-390 > > ---------------------------------------------------------------------- > > For more information on Linux on System z, visit > > http://wiki.linuxvm.org/ > > NOTICE: This e-mail correspondence is subject to Public Records Law > > and may be disclosed to third parties. –– > > NOTICE: This e-mail correspondence is subject to Public Records Law > > and may be disclosed to third parties. –– > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, send > email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit http://wiki.linuxvm.org/ > NOTICE: This e-mail correspondence is subject to Public Records Law and > may be disclosed to third parties. –– > NOTICE: This e-mail correspondence is subject to Public Records Law and > may be disclosed to third parties. –– > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
