Hi there,
I have a slightly non-traditional setup of a RHEL-6.4 box where it is
mirrored using LVM2 RAID-1 to a iSCSI target which is connected by the
RHEL-6 itself via open-iscsi after it boots.
I am not doing any ramdisk change to the box to connect to the iSCSI
while kernel is loading since I believe there is a way to do
incremental resynch of the RAID-1 after Linux boots.
Before the reboot, I have a healthy raid-1 between local disk (sda)
and iscsi disk (sdb):
[root@dg-test-rhel2 LinuxOnboarding]# lvs -a -o +seg_pe_ranges
LV VG Attr LSize Pool Origin Data%
Move Log Cpy%Sync Convert PE Ranges
lv_root vg_dgtestrhel1 rwi-aor-- 15.57g
100.00 lv_root_rimage_0:0-3985
lv_root_rimage_1:0-3985
[lv_root_rimage_0] vg_dgtestrhel1 iwi-aor-- 15.57g
/dev/sda2:0-3985
[lv_root_rimage_1] vg_dgtestrhel1 iwi-aor-- 15.57g
/dev/sdb2:1-3986
[lv_root_rmeta_0] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sda2:4866-4866
[lv_root_rmeta_1] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sdb2:0-0
lv_swap vg_dgtestrhel1 rwi-aor-- 3.44g
100.00 lv_swap_rimage_0:0-879
lv_swap_rimage_1:0-879
[lv_swap_rimage_0] vg_dgtestrhel1 iwi-aor-- 3.44g
/dev/sda2:3986-4865
[lv_swap_rimage_1] vg_dgtestrhel1 iwi-aor-- 3.44g
/dev/sdb2:3988-4867
[lv_swap_rmeta_0] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sda2:4867-4867
[lv_swap_rmeta_1] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sdb2:3987-3987
[root@dg-test-rhel2 LinuxOnboarding]# pvs -v
Scanning for physical volume names
PV VG Fmt Attr PSize PFree DevSize PV UUID
/dev/sda2 vg_dgtestrhel1 lvm2 a-- 19.51g 504.00m 19.51g
MNbVOF-3d8V-kOFB-Y1X4-6sgw-Ny24-9Knicq
/dev/sdb2 vg_dgtestrhel1 lvm2 a-- 21.87g 2.86g 21.88g
9hlSsu-I8Rc-2IMl-tQyb-NAf0-RqWO-LJBkRf
[root@dg-test-rhel2 LinuxOnboarding]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_dgtestrhel1 2 2 0 wz--n- 41.38g 3.35g
After I reboot the box, Linux will automatically connects to the iscsi
LUN but the mirror is broken (if I do any write, I only see disk
activity on sda):
[root@dg-test-rhel2 ~]# lvs -a -o +seg_pe_ranges
LV VG Attr LSize Pool Origin Data%
Move Log Cpy%Sync Convert PE Ranges
lv_root vg_dgtestrhel1 rwi-aor-- 15.57g
100.00 lv_root_rimage_0:0-3985
lv_root_rimage_1:0-3985
[lv_root_rimage_0] vg_dgtestrhel1 iwi-aor-- 15.57g
/dev/sda2:0-3985
[lv_root_rimage_1] vg_dgtestrhel1 iwi-a-r-- 15.57g
/dev/sdb2:1-3986
[lv_root_rmeta_0] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sda2:4866-4866
[lv_root_rmeta_1] vg_dgtestrhel1 ewi-a-r-- 4.00m
/dev/sdb2:0-0
lv_swap vg_dgtestrhel1 rwi-aor-- 3.44g
100.00 lv_swap_rimage_0:0-879
lv_swap_rimage_1:0-879
[lv_swap_rimage_0] vg_dgtestrhel1 iwi-aor-- 3.44g
/dev/sda2:3986-4865
[lv_swap_rimage_1] vg_dgtestrhel1 iwi-a-r-- 3.44g
/dev/sdb2:3988-4867
[lv_swap_rmeta_0] vg_dgtestrhel1 ewi-aor-- 4.00m
/dev/sda2:4867-4867
[lv_swap_rmeta_1] vg_dgtestrhel1 ewi-a-r-- 4.00m
/dev/sdb2:3987-3987
[root@dg-test-rhel2 ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 vg_dgtestrhel1 lvm2 a-- 19.51g 504.00m
/dev/sdb2 vg_dgtestrhel1 lvm2 a-- 21.87g 2.86g
[root@dg-test-rhel2 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
vg_dgtestrhel1 2 2 0 wz--n- 41.38g 3.35g
Please note that the [lv_root_rimage_1] and [lv_root_rmeta_1]
devices are no longer open even though LVM reports there is a mirror.
I am looking for a simple LVM command that could force the RAID-1
mirror to resynch (ideally incrementally since we have the bitmap
device which should track all the un-synched data). I am able to
convert the LV to Linear volumes and re-create the mirror once again
but that is very lame.
Please help!
Many thanks,
Shi
PS. My OS information
[root@dg-test-rhel2 ~]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 6.4 (Santiago)
[root@dg-test-rhel2 ~]# uname -a
Linux dg-test-rhel2.doe.local 2.6.32-358.el6.x86_64 #1 SMP Tue Jan 29
11:47:41 EST 2013 x86_64 x86_64 x86_64 GNU/Linux
[root@dg-test-rhel2 ~]# lvm version
LVM version: 2.02.98(2)-RHEL6 (2012-10-15)
Library version: 1.02.77-RHEL6 (2012-10-15)
Driver version: 4.23.6
[root@dg-test-rhel2 ~]#
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