Re: [linux-lvm] lvm raid1 metadata on different pv

[emmanuel segura]

I did as follow and it works, without storing the metadata on zram:

  truncate -s500M  disk1.dd
  truncate -s500M  disk2.dd
  losetup /dev/loop0 /root/disk1.dd
  losetup /dev/loop1 /root/disk2.dd

pvcreate /dev/loop0
pvcreate /dev/loop1
vgcreate vg00/dev/loop0 /dev/loop1
vgcreate vg00 /dev/loop0 /dev/loop1

lvcreate --type raid1 --name raid1vol -L 400M vg00

[root@puppetserver:~# lvs -ao +devices
  LV  VG   Attr LSize   Pool Origin Data%  Move Log
Copy%  Convert Devices
  raid1volvg00 rwi-a-m- 400.00m
100.00 raid1vol_rimage_0(0),raid1vol_rimage_1(0)
  [raid1vol_rimage_0] vg00 iwi-aor-
400.00m
/dev/loop0(1)
  [raid1vol_rimage_1] vg00 iwi-aor-
400.00m
/dev/loop1(1)
  [raid1vol_rmeta_0]  vg00 ewi-aor-
4.00m
/dev/loop0(0)
  [raid1vol_rmeta_1]  vg00 ewi-aor-
4.00m
/dev/loop1(0)

Now I will the metadata to other pvs:

truncate -s 100M meta1.dd
truncate -s 100M meta2.dd

 losetup /dev/loop2 meta1.dd
 losetup /dev/loop3 meta2.dd

 vgextend vg00 /dev/loop2
 vgextend vg00 /dev/loop3

pvmove -n 'raid1vol_rmeta_0' /dev/loop0 /dev/loop2
pvmove -n 'raid1vol_rmeta_1' /dev/loop1 /dev/loop3

vgchange -an vg00
  0 logical volume(s) in volume group "vg00" now active

vgchange -ay vg00
  1 logical volume(s) in volume group "vg00" now active




2017-09-25 11:30 GMT+02:00 Alexander 'Leo' Bergolth :

> Hi!
>
> I tried to move the raid1 metadata subvolumes to different PVs (SSD
> devices for performance).
>
> Moving with pvmove works fine but activation fails when both legs of the
> metadata had been moved to external devices. (See below.)
>
> Interestingly moving just one metadata LV to another device works fine.
> (Raid LV can be activated afterwards.)
>
> I guess raid1 metadata on different PVs is not supported (yet)?
>
> I am using Centos 7.4 and kernel 3.10.0-693.el7.x86_64.
>
> Cheers,
> --leo
>
>  8< 
> modprobe zram num_devices=2
> echo 300M > /sys/block/zram0/disksize
> echo 300M > /sys/block/zram1/disksize
>
> pvcreate /dev/sda2
> pvcreate /dev/sdb2
> pvcreate /dev/zram0
> pvcreate /dev/zram1
>
> vgcreate vg_sys /dev/sda2 /dev/sdb2 /dev/zram0 /dev/zram1
> lvcreate --type raid1 -m 1 --regionsize 64M -L 500m -n lv_boot vg_sys
> /dev/sda2 /dev/sdb2
>
> pvmove -n 'lv_boot_rmeta_0' /dev/sda2 /dev/zram0
> # and maybe
> # pvmove -n 'lv_boot_rmeta_1' /dev/sdb2 /dev/zram1
>
>  8< 
> Creating vg_sys-lv_boot
> dm create vg_sys-lv_boot LVM-l6Eg7Uvcm2KieevnXDjLLje3wqmSVG
> a1e56whxycwUR2RvGvcQNLy1GdfpzlZuQk [ noopencount flush ]   [16384] (*1)
> Loading vg_sys-lv_boot table (253:7)
>   Getting target version for raid
> dm versions   [ opencount flush ]   [16384] (*1)
>   Found raid target v1.12.0.
> Adding target to (253:7): 0 1024000 raid raid1 3 0 region_size
> 8192 2 253:3 253:4 253:5 253:6
> dm table   (253:7) [ opencount flush ]   [16384] (*1)
> dm reload   (253:7) [ noopencount flush ]   [16384] (*1)
>   device-mapper: reload ioctl on  (253:7) failed: Input/output error
>  8< 
> [ 8130.110467] md/raid1:mdX: active with 2 out of 2 mirrors
> [ 8130.111361] mdX: failed to create bitmap (-5)
> [ 8130.112254] device-mapper: table: 253:7: raid: Failed to run raid array
> [ 8130.113154] device-mapper: ioctl: error adding target to table
>  8< 
> # lvs -a -o+devices
>   LV VG Attr   LSize   Pool Origin Data%  Meta%
> Move Log Cpy%Sync Convert Devices
>   lv_bootvg_sys rwi---r--- 500.00m
>  lv_boot_rimage_0(0),lv_boot_rimage_1(0)
>   [lv_boot_rimage_0] vg_sys Iwi-a-r-r- 500.00m
>  /dev/sda2(1)
>   [lv_boot_rimage_1] vg_sys Iwi-a-r-r- 500.00m
>  /dev/sdb2(1)
>   [lv_boot_rmeta_0]  vg_sys ewi-a-r-r-   4.00m
>  /dev/zram0(0)
>   [lv_boot_rmeta_1]  vg_sys ewi-a-r-r-   4.00m
>  /dev/zram1(0)
>  8< 
>
> Full vgchange output can be found at:
>   http://leo.kloburg.at/tmp/lvm-raid1-ext-meta/
>
>
> --
> e-mail   ::: Leo.Bergolth (at) wu.ac.at
> fax  ::: +43-1-31336-906050
> location ::: IT-Services | Vienna University of Economics | Austria
>
> ___
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>



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Re: [linux-lvm] clvm: failed to activate logical volumes sometimes

[emmanuel segura]

maybe you are using an old clvm version, I rember that in the new
version you don't need to execute any command on the secondary node.

2017-04-20 10:06 GMT+02:00 Eric Ren :
> Hi!
>
> This issue can be replicated by the following steps:
> 1. setup two-node HA cluster with dlm and clvmd RAs configured;
> 2. prepare a shared disk through iscsi, named "sdb" for example;
>
> 3. execute lvm cmds on n1:
> lvm2dev1:~# pvcreate /dev/sdb
> Physical volume "/dev/sdb" successfully created
> lvm2dev1:~ # vgcreate vg1 /dev/sdb
> Clustered volume group "vg1" successfully created
> lvm2dev1:~ # lvcreate -l100%VG -n lv1 vg1
> Logical volume "lv1" created.
> lvm2dev1:~ # lvchange -an vg1/lv1
>
> 4. disconnect shared iscsi disk on n2;
> 5. to activate vg1/lv1 on n1:
> lvm2dev1:~ # lvchange -ay vg1/lv1
> Error locking on node UNKNOWN 1084783200: Volume group for uuid not
> found: TG0VguoR1HxSO1OPA0nk737FJSQTLYAMKV2M20cfttItrRnJetTZmKxtKs3a88Ri
>
> 6. re-connect shared disk on n2;
> 7. execute `clvmd -R` on n1; and then I can activate lv1 successfully.
>
> In local mode, lvm will make a full scan on disks each time when lvmetad is
> disable. As we know,
> lvmetad is also disable when clvm is in use, so that  device cache can not
> be refreshed automatically
> when device is added or removed. We can solve this issue by executing "clvmd
> -R" manually. But,
> in some auto scripts, it's boring to put "clvmd -R" before some lvm commands
> everywhere.
>
> So, is there an option to enable full scan every time when lvm is invoked in
> cluster scenario?
> Thanks in advance:)
>
> Regards,
> Eric
>
> On 04/14/2017 06:27 PM, Eric Ren wrote:
>>
>> Hi!
>>
>> In cluster environment, lvcreate/lvchange may fail to activate logical
>> volumes sometimes.
>>
>> For example:
>>
>> # lvcreate -l100%VG -n lv001 clustermd
>>Error locking on node a52cbcb: Volume group for uuid not found:
>> SPxo6WiQhEJWDFyeul4gKYX2bNDVEsoXRNfU3fI5TI9Pd3OrIEuIm8jGtElDJzEy
>>Failed to activate new LV.
>>
>> The log file for this failure is attached. My thoughts on this issue
>> follows, for example on two nodes:
>> n1:
>> ===
>> #lvchange -ay vg/lv1
>> ...
>> clvmd will ask for peer daemon on n2
>> to activate lv1 as well
>>
>> n2:
>> ===
>> lvm need to find lv1 and the PVs for lv1,
>> in device cache which aims to avoid frequent scan all
>> disks. But if the PV(s) might not be available
>> in device cache, it responses n1 with errors
>>
>> We found that 'clvmd -R' can be a workaround before activating LV, because
>> what "clvmd -R" is to refresh device cache on every node as its commit
>> message said:
>> ===
>> commit 13583874fcbdf1e63239ff943247bf5a21c87862
>> Author: Patrick Caulfield 
>> Date:   Wed Oct 4 08:22:16 2006 +
>>
>>  Add -R switch to clvmd.
>>  This option will instruct all the clvmd daemons in the cluster to
>> reload their device cache
>> ==
>>
>> I think the reason why clvm doesn't refresh device cache every time before
>> activating LV,
>> is to avoid scanning all disks frequently.
>>
>> But, I'm not sure if I understand this issue correctly, will appreciate
>> much if someone can
>> help.
>>
>> Regards,
>> Eric
>>
>>
>>
>>
>> ___
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>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
>
>
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Re: [linux-lvm] Copying a raw disk image to LVM2

[emmanuel segura]

the lvm metadata is stored in the begining of the physical volume, the
logical volume is simple block device, so using dd you don't overwrite
any lvm header.

2016-07-09 19:33 GMT+02:00 Марк Коренберг :
> One note: `sync` does not syncs written data, since it affects only
> data, written through filesystem. You should use `dd 
> conv=fdatasync` instead.
>
> 2016-07-09 22:00 GMT+05:00 Digimer :
>> On 08/07/16 11:52 AM, Brian McCullough wrote:
>>>
>>> I have been hunting for some time over the past couple of days, and find
>>> several documentss that talk about converting from an LVM2 volume to a
>>> raw disk image for Xen, but nothing about the reverse.
>>>
>>> I have a VHD disk file that I would like to put on to an LVM2 volume,
>>> like my other DomU guests.
>>>
>>> I can see using dd, but am concerned about overwriting the LVM2 header.
>>>
>>>
>>> Does anybody have any suggestions?
>>
>> I've done this with KVM before just fine. The LV metadata won't be
>> overwritten when you write to the actual LV. So this would work fine;
>>
>> dd if=/path/to/image.raw of=/dev/vg0/lv_foo bs=4M; sync
>>
>> Then just change your server's definition to point at the LV instead of
>> the raw file and voila.
>>
>> --
>> Digimer
>> Papers and Projects: https://alteeve.ca/w/
>> What if the cure for cancer is trapped in the mind of a person without
>> access to education?
>>
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>
>
>
> --
> Segmentation fault
>
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