![LVM 镜像,数据和日志镜像在相同的 2 个设备上](https://linux22.com/image/800919/LVM%20%E9%95%9C%E5%83%8F%EF%BC%8C%E6%95%B0%E6%8D%AE%E5%92%8C%E6%97%A5%E5%BF%97%E9%95%9C%E5%83%8F%E5%9C%A8%E7%9B%B8%E5%90%8C%E7%9A%84%202%20%E4%B8%AA%E8%AE%BE%E5%A4%87%E4%B8%8A.png)
我正在尝试设置只有 2 个设备的 LVM 镜像。当我为 mirrorlog 添加第三个设备或使用 corelog 时,它工作得很好。但只有 2 个设备并且--在任何地方分配LVM 几乎总是在一个设备上创建两个镜像。
情况:
- 2 x 50GB 设备 /dev/xvdf 和 /dev/xvdg
- 我需要在 /dev/xvdf 上创建一个 40GB 的分区,该分区将在 /dev/xvdg 上进行镜像
- 我不希望有 2 个单独的驱动器用于镜像日志,我希望镜像日志位于 /dev/xvdf 和 /dev/xvdg 上(在某些范围内)
问题:
LVM 几乎总是(如果我正确理解了 lvs 命令输出)在 /dev/xvdf 上创建镜像,在 /dev/xvdg 上创建镜像日志(是的 :-(
我使用的命令:
场景 1-最简单:
$ lvcreate -m 1 --mirrorlog mirrored -L40G -n test forfiter --alloc anywhere
$ lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices
test forfiter mwa-a- 40,00g test_mlog 7,09 test_mimage_0(0),test_mimage_1(0)
[test_mimage_0] forfiter Iwi-ao 40,00g /dev/xvdf(0)
[test_mimage_1] forfiter Iwi-ao 40,00g /dev/xvdf(10240)
[test_mimage_1] forfiter Iwi-ao 40,00g /dev/xvdg(2)
[test_mlog] forfiter mwa-ao 4,00m 100,00 test_mlog_mimage_0(0),test_mlog_mimage_1(0)
[test_mlog_mimage_0] forfiter iwi-ao 4,00m /dev/xvdg(0)
[test_mlog_mimage_1] forfiter iwi-ao 4,00m /dev/xvdg(1)
如您所见,test_mimage_1 部分位于 /dev/xvdf,部分位于 /dev/xvdf。xvdf 上分配了 12799 PE,xvdg 上分配了 7683 PE。
最有趣的是 LVM 也在一个设备上创建了 mlog......
场景 2-我尝试指定要使用的区数:
$ lvcreate -m 1 --mirrorlog mirrored -L 40G -n test forfiter /dev/xvdf:6-12700 /dev/xvdg:6-12700 /dev/xvdf:0-4 /dev/xvdg:0-4 --alloc anywhere
$ lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices
test forfiter mwa-a- 40,00g test_mlog 2,79 test_mimage_0(0),test_mimage_1(0)
[test_mimage_0] forfiter Iwi-ao 40,00g /dev/xvdf(6)
[test_mimage_1] forfiter Iwi-ao 40,00g /dev/xvdf(10246)
[test_mimage_1] forfiter Iwi-ao 40,00g /dev/xvdf(0)
[test_mimage_1] forfiter Iwi-ao 40,00g /dev/xvdg(7)
[test_mlog] forfiter mwa-ao 4,00m 100,00 test_mlog_mimage_0(0),test_mlog_mimage_1(0)
[test_mlog_mimage_0] forfiter iwi-ao 4,00m /dev/xvdg(6)
[test_mlog_mimage_1] forfiter iwi-ao 4,00m /dev/xvdg(0)
没有成功:-)
我读了很多教程——作者建议使用--在任何地方分配但对我来说,结果看起来很奇怪(镜像有效,但不像我预期的那样)
我想将 raid1 从 MDADM 迁移到 LVM。
答案1
使用分区编辑器(例如parted
、cfdisk
或 )fdisk
创建分区:/dev/xvdf1
和/dev/xvdf2
等,并将它们放入您的forfiter
VG。
在这个例子中我使用/dev/mapper/loop0p1
等等。
pvcreate /dev/mapper/loop1p1
Physical volume "/dev/mapper/loop1p1" successfully created
pvcreate /dev/mapper/loop1p2
Physical volume "/dev/mapper/loop1p2" successfully created
vgcreate forfiter /dev/mapper/loop0p1
Volume group "forfiter" successfully created
vgextend forfiter /dev/mapper/loop1p1
Volume group "forfiter" successfully extended
vgextend forfiter /dev/mapper/loop0p2
Volume group "forfiter" successfully extended
vgextend forfiter /dev/mapper/loop1p2
Volume group "forfiter" successfully extended
vgs forfiter
VG #PV #LV #SN Attr VSize VFree
forfiter 4 0 0 wz--n- 248.00m 248.00m
ls -l /dev/mapper/loop0p1
lrwxrwxrwx 1 root root 8 Apr 18 08:59 /dev/mapper/loop0p1 -> ../dm-21
vgdisplay -v forfiter | tail -n mumble
--- Physical volumes ---
PV Name /dev/dm-21
PV UUID uFJpEH-dLFA-gJiM-cnao-cFFm-DEZG-RnNvSM
PV Status allocatable
Total PE / Free PE 15 / 15
PV Name /dev/dm-23
PV UUID 1T7DIL-Xw4s-4tVy-CVQc-lKDp-aUNA-lyk8v2
PV Status allocatable
Total PE / Free PE 15 / 15
PV Name /dev/dm-22
PV UUID T0prpa-KKEO-uWUb-zQU3-cosM-uyEI-ext9F7
PV Status allocatable
Total PE / Free PE 16 / 16
PV Name /dev/dm-24
PV UUID PC2aCZ-eKdU-p8eS-SBDc-uWzY-54gG-952ndg
PV Status allocatable
Total PE / Free PE 16 / 16
lvcreate -m 1 --mirrorlog mirrored -L64M -n test forfiter
The link /dev/forfiter/test_mlog should had been created by udev but it was not found. Falling back to direct link creation.
The link /dev/forfiter/test_mlog should have been removed by udev but it is still present. Falling back to direct link removal.
Logical volume "test" created
lvs -a -o +devices forfiter
LV VG Attr LSize Origin Snap% Move Log Copy% Convert Devices
test forfiter mwi-a- 64.00m test_mlog 100.00 test_mimage_0(0),test_mimage_1(0)
[test_mimage_0] forfiter iwi-ao 64.00m /dev/dm-22(0)
[test_mimage_1] forfiter iwi-ao 64.00m /dev/dm-24(0)
[test_mlog] forfiter mwi-ao 4.00m 100.00 test_mlog_mimage_0(0),test_mlog_mimage_1(0)
[test_mlog_mimage_0] forfiter iwi-ao 4.00m /dev/dm-21(0)
[test_mlog_mimage_1] forfiter iwi-ao 4.00m /dev/dm-23(0)
答案2
如果没有创建分区,你的问题是你正在使用相同的命令"--mirrorlog mirrored and --alloc anywhere"
我在 suse 11 上遇到了同样的问题,"--mirrorlog mirrored"
但我通过以下方式使用 lvm 命令解决了这个问题:
lvcreate -m 1 --mirrorlog mirrored -L40G -n test forfiter /dev/xvdb /dev/xvdc
在 redhat 或 centos 中,你可以在 lvm.conf 中找到此注释
# Set to 1 to guarantee that mirror logs will always be placed on
# different PVs from the mirror images. This was the default
# until version 2.02.85.
mirror_logs_require_separate_pvs = 0
有很多方法可以解决这个问题,无需创建分区。