Hello, I am running a server with Debian stable. After a recent automatic update and an unrelated reboot suddenly I could not mount some of my hard disks any more. For example, mount /dev/sda1 /mnt gave me mount: /dev/sda1 already mounted or /mnt busy It took me quite a while to figure out that it is the device mapper that makes /dev/sda1 busy. For whatever reason, there are now the files /dev/dm-0, /dev/dm-1 and /dev/dm-2 that correspond to /dev/sda, /dev/sda1 and /dev/sda2. I assume they have been created by the dev mapper. The server has been running for ages, has a relatively complex setup and has been through a number of configurations. However, I never really used dev mapper. My questions are as follows: 1) does dev mapper somehow automatically gets hold of my /dev/sda, or is there a configuration file somewhere (maybe a stale configuration that got used after the update? I used to have an lvm, but I got rid of it. Never on purpose used multipath-tools or dm-crypt). My suspicion is that it is due to multipath, as multipath -l shows 3600d0230006c1c550bdc214a99d0c000dm-0 Transtec,PV610F16R1B [size=2.7T][features=0][hwhandler=0] \_ round-robin 0 [prio=0][active] \_ 3:0:0:0 sda 8:0 [active][undef] ...but I never told multipath to do that! Running multipath -v 3 -l shows that there are some disks that are "blacklisted": cciss!c0d0: blacklisted cciss!c0d1: blacklisted dm-0: blacklisted dm-1: blacklisted dm-2: blacklisted fd0: blacklisted ... Are they blacklisted automatically or is there a way to do it manually? 2) how do I switch off device mapper for /dev/sda*? I just want to use my plain /dev/sda1 and /dev/sda2. I don't want to change any of my working configuration, I am happy with what it is now. For now, I have mounted /dev/dm-1 and /dev/dm-2, but I don't understand them and what I don't understand I don't want :-). I tried to deinstall dmsetup and multipath-tools and running /etc/init.d/multipath-tools stop, but without success. 3) what would be a reason to keep these /dev/dm-* mappings? multipath i/o? 4) next time -- how do I find out what is using /dev/sda1? I only figured out what is going on by looking at /proc/partitions; no standard tools that I normally use (fuser, lsof, lsmod etc.) did not report anything curious. Best regards, j. -- ---------Dr. January Weiner 3 ---------------------+--------------- Division of Bioinformatics, University of Muenster | Schloßplatz 4 (+49)(251)8321634 | D48149 Münster http://www.uni-muenster.de/Evolution/ebb/ | Germany -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
