Hi, I am trying to add a new resiliency type to LVM, which I call dyre - dynamic reliability. As a first step, I plan to create a simple striped volume, similar to what we can get using the below command: lvcreate -i 2 -I 8 -L 30M -n root vol_vg this will create a volume "root' in volume group "vol_vg" of size 30MB with 2 stripes and stripesize of 8KB. I have added relevant code in lvm so that the command gives the same results as above: lvcreate --type dyre --stripes --stripesize 8 -L 30M -n root vol_vg However, I notice that in first case, when lvm creates the volume named root, it creates a soft link to /dev/dm-0 : $ ls -alrt /dev/vol_vg/root lrwxrwxrwx 1 root root 23 Nov 19 15:35 /dev/vol_vg/root -> /dev/mapper/vol_vg-root $ ls -alrt /dev/mapper/vol_vg-root lrwxrwxrwx 1 root root 9 Nov 19 15:36 /dev/mapper/vol_vg-root -> /dev/dm-0 If I run my command (the second command with my new defined resiliency type) using gdb, place a breakpoint before the function - dev_cache_get() and in a new terminal check for file /dev/vol_vg/root file, it exists but only as an archive file (i.e., there is no link between /dev/mapper/vol_vg-root and /dev/dm-0). Since there is no actual device linked to the file, functions like stat() that are used in dev_cache_get() code return error - no such file or directory which results in unsuccessful volume creation. I also noticed that the temporary file is deleted by lvm. I think the part of code that does this linking is in device mapper code, but I am not sure where this is being done. Furthermore, when I create a link artifically by using the command ln -s /dev/dm-0 /dev/mapper/vol_vg-root and resume from breakpoint, my volume gets created. I need some help regarding which code in lvm does this linking of archive (temporary?) file to /dev/dm-0. Thanks, -- Shehbaz Jaffer First Year Graduate Student Sir Edward S Rogers Sr Department of Electrical and Computer Engineering University of Toronto -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
