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presenting luns from linux host to another
we have an old linux host that it lost it's boot disk and won't boot up anymore. What we did is we moved those luns to another linux host. There are 9 luns all together. from the other linux host, we did a rescan:
1. echo "- - -" > /sys/class/scsi_host/host3/scan (bus scan) (starting with host0)
2.pvscan
pvscan
PV /dev/emcpoweri1 VG VolGroup01 lvm2 [50.00 GB / 10.00 GB free]
PV /dev/emcpowern VG vg_data lvm2 [110.00 GB / 0 free] ==> lun from old host
PV /dev/emcpowert VG vg_data lvm2 [120.00 GB / 0 free] ==> lun from old host
PV /dev/emcpowerm VG vg_data lvm2 [650.00 GB / 0 free ==> lun from old host]
PV /dev/sda5 VG VolGroup00 lvm2 [273.56 GB / 128.09 GB free]
PV /dev/sda2 VG VolGroup00 lvm2 [5.00 GB / 5.00 GB free]
Total: 6 [1.18 TB] / in use: 6 [1.18 TB] / in no VG: 0 [0 ]
NOTE: only 3 LUNS/Volumes are showing up. We enabled the 'vg_data' volume group and was able to mount those volumes.
so we are missing 6 other LUNS and those aren't showing up as part of a Volume Group.
this are the 9 luns from the Clariion array:
HLU Number ALU Number
---------- ----------
0 82
1 120
2 121
3 160
4 83
5 150
6 81
7 84
8 85
POWERPATH shows all luns.
pvdisplay -C --separator ' | ' -o pv_name,vg_name
PV | VG
/dev/emcpoweri1 | VolGroup01
/dev/emcpowerm | vg_data
/dev/emcpowern | vg_data
/dev/emcpowert | vg_data
/dev/sda2 | VolGroup00
/dev/sda5 | VolGroup00
WE do not know what luns belongs to what VG since the original host is already gone/won't boot.
Is there any idea on what to look at to figure out the VGs of the other LUNs that are NOT showing on PVSCAN ?
Thanks. We need to recover those data.
dynamox
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May 10th, 2015 19:00
assuming the host was being backed up, anything of use in /etc/lvm directory (if you can restore that) ?
dsalud1
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May 10th, 2015 21:00
unfortunately, we don't have any backup for that server that died. It was a legacy system and we were supposed to decomm this server last week but we realized we need to archive some files from it but it was too late.
dynamox
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May 10th, 2015 21:00
output from "pvs --segments" does not provide any hints ? We swing devices from one system to another often when we do system refreshes/backup (moving snapshots). They are graceful though (unmount, vg de-activate, vg export/ vgimport, vg-activate, mount). I am just wondering if lvm header got corrupted or something.
dsalud1
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May 10th, 2015 22:00
i don't know what else I can do. Usually, after rescan and you do a pvscan, it should show all the VGs with all the volumes. in this case, a VG showed up with only 3 volumes and I don't know what happened to the 6 of the luns.
dynamox
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May 11th, 2015 03:00
what does output from "pvs --segments" look like ?
dsalud1
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May 11th, 2015 06:00
[root@srac2 ~]# pvs --segments
PV VG Fmt Attr PSize PFree Start SSize
/dev/emcpoweri1 VolGroup01 lvm2 a- 50.00G 10.00G 0 10240
/dev/emcpoweri1 VolGroup01 lvm2 a- 50.00G 10.00G 10240 2559
/dev/emcpowerm vg_data lvm2 a- 650.00G 0 0 28160
/dev/emcpowerm vg_data lvm2 a- 650.00G 0 28160 30720
/dev/emcpowerm vg_data lvm2 a- 650.00G 0 58880 107519
/dev/emcpowern vg_data lvm2 a- 110.00G 0 0 28159
/dev/emcpowert vg_data lvm2 a- 120.00G 0 0 30719
/dev/sda2 VolGroup00 lvm2 a- 5.00G 5.00G 0 160
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 0 128
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 128 128
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 256 192
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 448 128
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 576 256
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 832 815
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 1647 832
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 2479 384
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 2863 192
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 3055 768
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 3823 832
/dev/sda5 VolGroup00 lvm2 a- 273.56G 128.09G 4655 4099
dynamox
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May 11th, 2015 07:00
what was the name of the volume group ? Are you sure those devices were part of a volume group and not mounted directly ?
dsalud1
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May 11th, 2015 09:00
i don't have that info actually because the original server died before I got to it but our DBAs said there are 2 other mount points that starts with Ora*. I am just hoping after presenting those 9 luns to another host of similar OS and LVM, the VGs will just come up.
kelleg
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May 11th, 2015 10:00
Did you match the HLU/ALU numbers to match what it was in the old Storage Group or did you just add a new host to the existing Storage Group? Maybe the order of the HLU numbers changed (I know nothing about Unix)? Did you check that the new host has connection to each LUN in the Storage Group from all paths?
glen
dynamox
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May 11th, 2015 10:00
it does not matter how you present the LUNs, LVM is smart enough to find the devices that matching the LVM header.
kelleg
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May 11th, 2015 10:00
That's the part that I'm not sure about as I really don't know Linux, but I was thinking that if there is any linking between the LUNs and it uses the HLU number and if that number changed with the new host, then the links might not work.
glen
dsalud1
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May 11th, 2015 10:00
powerpath sees all 9 luns
dsalud1
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May 11th, 2015 10:00
Hi Glen,
I presented all the 9 LUNS with HLUs matching their LUN ID numbers. I can change the HLUs to match how they are presented to the original host and go from there. Will that make a difference from the linux side?
dsalud1
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May 11th, 2015 10:00
LVM does not see other VGs is my main concern
dsalud1
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May 12th, 2015 16:00
i was able to get a snapshot of the /etc/fstab of the original host from one of the guys who used to work on that server. 3 of those LUNS are not part of a VG so I mounted them indivudally and the other 3 LUNS are part of the VG of the same name and just mount them as well. This is really hard to figure out if you don't have the lvm.conf and the /etc/fstab. I am a happy camper now ! thanks to those who tried to help me! I appreciate it.