On Mon, 2009-08-31 at 12:02 -0400, Takahiro Yasui wrote: > On 08/31/09 11:16, Alan D. Brunelle wrote: > > I constructed a 1-copy mirror with the following commands: > > > > # pvcreate --metadatasize 192k /dev/sdcn /dev/sdfj /dev/sdfa > > Physical volume "/dev/sdcn" successfully created > > Physical volume "/dev/sdfj" successfully created > > Physical volume "/dev/sdfa" successfully created > > # vgcreate vg /dev/sdcn /dev/sdfj /dev/sdfa > > Volume group "vg" successfully created > > # lvcreate -L 32g -m 1 -n lv vg > > Logical volume "lv" created > > > > The status showed: > > > > # lvs -a -o +devices > > LV VG Attr LSize Origin Snap% Move Log Copy% > > Convert Devices > > lv vg mwi-a- 32.00G lv_mlog 29.72 > > lv_mimage_0(0),lv_mimage_1(0) > > [lv_mimage_0] vg Iwi-ao > > 32.00G /dev/sdcn(0) > > [lv_mimage_1] vg Iwi-ao > > 32.00G /dev/sdfj(0) > > [lv_mlog] vg lwi-ao > > 4.00M /dev/sdfa(0) > > > > Then I forced /dev/sdfj to fail (removing the unit from the FC SAN), and > > the state of the mirror went to: > > > > # lvs > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > LV VG Attr LSize Origin Snap% Move Log Copy% Convert > > lv vg -wi-a- 32.00G > > > > At this point I know I can do: > > > > # vgreduce -a vg > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > Physical volume "/dev/sdcn" still in use > > Removed "/dev/sdfa" from volume group "vg" > > > > But I run into two problems: > > > > (1) I'd like to be able to live without the constant errors > > about /dev/sdfj, and tried: > > > > # pvremove -f /dev/sdfj > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > No physical volume label read from /dev/sdfj > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > Labels on physical volume "/dev/sdfj" successfully wiped > > > > but that didn't stop it. > > > > and: > > > > (2) I'd like to be able to recreate the 1-copy mirror from the currently > > linear volume, but can't (easily): > > > > # pvcreate --metadatasize 192k /dev/sdp > > Physical volume "/dev/sdp" successfully created > > # vgextend vg /dev/sdp > > ... errors from sdfj omitted... > > Volume group "vg" successfully extended > > # vgs > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > VG #PV #LV #SN Attr VSize VFree > > vg 2 1 0 wz--n- 542.67G 510.67G > > # lvconvert -m 1 /dev/vg/lv > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > Insufficient suitable allocatable extents for logical volume : 8192 > > more required > > Unable to allocate extents for mirror(s). > > > > I can use the alloc anywhere options, but I'm at a loss as to why that's > > needed: > > > > # lvconvert -m1 --alloc anywhere /dev/vg/lv > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > /dev/vg/lv: Converted: 1.3% > > /dev/vg/lv: Converted: 2.6% > > /dev/vg/lv: Converted: 3.8% > > ... > > > > > > Any pointers on how to remove /dev/sdfj from the scan (other than, I > > guess, updated /etc/lvm.conf to filter it out) > > The following URL explains how to remove lost PVs from VG. > > 6.6. Removing Lost Physical Volumes from a Volume Group > http://www.redhat.com/docs/manuals/enterprise/RHEL-5-manual/Cluster_Logical_Volume_Manager/lost_PV_remove_from_VG.html > > I think "vgreduce --removemissing vg" will remove "/dev/sdfj." I guess this is an interesting problem: > > > # vgreduce -a vg > > > /dev/sdfj: read failed after 0 of 2048 at 0: Input/output error > > > Physical volume "/dev/sdcn" still in use > > > Removed "/dev/sdfa" from volume group "vg" > > So, /dev/sdfa was removed from the volume group instead of /dev/sdfj (Why? /dev/sdfa was being used for the mirror log - but since the volume group was downgraded to a linear array, it was no longer needed? Doesn't sound like the right thing to do - hence I should have used the --test and worked it out from that). I'll go retry the experiment and do the "removemissing" command. And since /dev/sdfa was removed & /dev/sdfj was failed that left only a single physical disk in the VG, then when I added in /dev/sdp it only brought the volume group to two devices. <sigh> > > > or an explanation as to > > why the 'alloc anywhere' is needed for the lvconvert would be muchly > > appreciated. > > To create a mirror volume with disk log, three PVs are required in the VG > to allocate two mirror legs and one mirror log. But in this case, the "vg" > contains only two valid PVs (/dev/sdcn and /dev/sdp), and '--alloc anywhere' > options is necessary to allocate a mirror log on the same disk as mirror legs. > > I hope this would be help. > > Thanks, > Taka > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
