Data migrate with XP Continuous Access

[Massimo_20]

Hi,
i must use HP XP Continuous Access to migrate data between two storage.

My server is linked to both storage.

Have somebody a tested procedure?

Thanks in advanced.

[Ninad_1]

Hi,

You have 2 options.
1. Connect the 2 storage arrays using ESCON links (Your HP storage admin should be able to tell you more on this), setup CA on these arrays, configure similar LUNs on the target array, configure CA PVOL and SVOL relation for the source and target LUNs and then synchronise. This depends on which arrays you are connecting and if CA is supported between these arrays.

But for this you require CA licenses = 2 * amount of storage to be replicated.

2. If your MAX PV value for the VGs on source can accomodate disks (from the target Storage arrays), then you can do a mirroring of all the LVs at LVM level and then simply reduce the mirror from the source disks and then reduce the VG to remove the source disks.

It all depends on how much time you have for synchronisation, there may be a bit of impact on performance if done at server level (method 2), how much budget you have etc.

Hope this helps,
Ninad

[Massimo_20]

I must use the CA method.
I have already connect the 2 storage arrays. Now, I have 2 LDEV (PVOL and SVOL) whith the same data, but only pvol is used by the server. For migrate to svol from pvol, i think use this procedure:
pvcreate svol
vgexport MyVG PVOL
vgcreate MyVG SVOL

I have doubts about use pvcreate!
Thanks

[Ninad_1 · Accepted solution]

You should not use pvcreate.
When you do the CA synchronisation and then split the pairs, due to the synchronisation all the bit by bit data from one LDEV(PVOL) is already been copied/mirrored to the other LDEV(SVOL).
Infact this causes even the VGDA information to be copied to the target LUNs.
Thus now, after splitting, suppose you want to import the VGs as seperate VGs for instance, so that you can check source and target - then follow below procedure.

1. Create the directories for the targte VGs.
e.g. mkdir /dev/vg01.ca
2. Create the group files for each VG
e.g. mknod /dev/vg01.ca/group c 64 0x310000
(Note that the minor number should be unique in that server and check the maxvgs kernel parameter to check upto how many VGs you can create - if this value is not allowing you to have all the required no. of VGs , then you will have to increase this parameter and rebuild kernel)
3. Change the VGID of the target LUNs.
e.g. if say c21t0d0, c21t0d1 and c21t0d2 are the target LUNS (SVOLS) for vg01, then
vgchgid /dev/rdsk/c21t0d0 /dev/rdsk/c21t0d1 /dev/rdsk/c21t0d2
4. Create map file from source VG without actually exporting it.
e.g. vgexport -p -m vg01.map
(Note that -s is not used as it records the VGID and you would be changing the VGID in step 4)
5. Import the target VG (SVOLS)
vgimport -v -m vg01.map /dev/vg01.ca /dev/dsk/c21t0d0 /dev/dsk/c21t0d1 /dev/dsk/c21t0d2
6. Activate the VGs
vgchange -a y /dv/vg01.ca
7. Extend VG to use alternate path {if there is alternate path]
vgextend /dev/vg01.ca /dev/dsk/c41t0d0 /dev/dsk/c41t0d1 /dev/dsk/c41t0d2
(Assuming c41t0d0 is alternate path for c21t0d0)
8. Mount the filesystems on temporary mount points (which you need to create accordingly)
9. Test.

I hope this is much it.

Regards,
Ninad

[Massimo_20]

Ok, now it's all clear!

Thank you so much.
Gianni