What are the steps to be followed from OS side to migrate Hitachi storage to EMC symmetrix in HPUX B.11.23 ?
I am planning to do it with mirroring, is it right menthod ? I heard this can done in storage level through storage software is it true ? what are different methods avaliable to do storage migration ? which is the best ?
Please suggest me a plan of action and the things to be careful of while doing this. what are the best practice followed from OS side while doing a storage migration ?
Mirroring is an optional product and if you have it installed on the server it will work as long as you can access both storage systems at the same time.
Do it during the off-peak hours because expanding/mirroring the LVOLs from one storage system to the other requires significant server i/o.
Also be careful when you break the mirrors to remove the Hitachi PVs, ensure that the mirrors are in good state, check with "vgdisplay -v" and "lvdisplay -v" and look for the "synced" status.
You can also do it with pvmove.
For storage migration at the storage level, it depends on the tools that are available and the interoperability between the two storage systems. I think it requires some downtime whe you cut over the LUNs after you sync them.
we have done storage migration twice now. But we always had only one manufacturer (netapp), and we had a downtime. We just did a copy on storage base, then unmount (nfs-)storage, doing a diffential copy again (for files which have changed after the first copy), modify fstab at server, then mount new storage. At least, check availability of datas.
Talk to your EMC technicians, and yes, doing it from the array level is quite feasible. You would need to create all new mapfiles for all vg's. Then when the disks are mirred onto the new array, the old disks are split off and you basically do a fresh vgimport on all your vg's which then picks up all the new mirrored disks. A little simpler than host-based, but still requires knowing the disk mappings (old disk 2 new disk).
If you prefer to do 'host based' from one array to another, you can. You would need to run cable additional fiber cable from the hosts to your switch/director; then have these connections zoned and disks will have to be mapped and masked for each host as well. Then I recommend you map out every old disk to it's new disk (on paper) by volume group. Then add these new disks to the vg an then lvextend -m for each lvol in every vg. Once mirrored, then remove your old disk from the lvol and finally from the vg. Be careful with striped/mirrored disks in vg's when doing this. And your done....
I think you see that host-based requires alot of internal work, but if you do it right it really let's you know your good.
The first option will cost more, the second will cost you in time and effort. Both will cost you in project stress.
