On 08/31/09 12:55, Alan D. Brunelle wrote: > 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> When you executed "vgreduce -a vg," the mirror volume, "lv", had already been converted to non-mirror (linear) volume. The linear device is not a mirror device any more, and a log disk is not used. So /dev/sdfa was removed since it was not used. I'm not sure why a missing device is not removed by "vgreduce -a vg," but vgreduce provides an option to remove a missing device and we can use it instead of executing "vgreduce -a." Thanks, Taka -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
