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migration of data from storage work to EMC storage

Occasional Visitor

migration of data from storage work to EMC storage

we are planning to migrate our data from HSG80 to the EMC Storage. Host is currently using secure path, and EMC requires powerpath and these storages are not on the same SAN. they are different. My question is that in theory I can add the new disk from EMc storage, from there I will perform the pvmove..from the LVM perpective I know what to do.. I am just a little hestitate on the actual how would I connect the host to two different SAN and two different storage..

thanks for your help
Exalted Contributor

Re: migration of data from storage work to EMC storage

In theory you can do this.

In general for such migrations I shut downt he databases, run an fbackup to tape, break and build the logical volumes and restore.

Its slow, but it gives me more than one chance to make a mistake.

Steven E Protter
Owner of ISN Corporation
Occasional Visitor

Re: migration of data from storage work to EMC storage

how will I establish the connection to EMC SAN, when 2 fiber cards are already connected to the HSG storage ?? Should I ISL the two SAN together?? By doing so
, ISL them together...eventually I will have to disconnect them?... is getting there an easier way to do this?? ori can break one of the HBA from HSG and cable it to EMC SAN.... and once i am done with the rest of the move... I can move the stuff back..
or I can create a map file for a volume group and import the volume group1 back using the different device??what do you guys think??
Honored Contributor

Re: migration of data from storage work to EMC storage


I don't know how secure path will respond if you drop one path. We always do this at our site.

There are two ways you can accomplish this. To simplify, take vg01 with only one disk with two paths (/dev/dsk/c1t0d0 and /dev/dsk/c2t0d0). Repeat this step for all VGs and the disks in them.

1. Disable secure path (if it is bothered about alternate link).
2. Reduce the alternate link.

vgreduce vg01 /dev/dsk/c2t0d0

3. It is now safe to replace the cable on th e alternate path to HSG80 with the cable going to EMC storage.

4. Run ioscan -f followed by insf. Determine the device file say /dev/dsk/c4t0d0.

pvcreate /dev/rdsk/c4t0d0

Here you can follow two approaches

Method 1: Extend the mirrors and reduce the mirrors

lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/c4t0d0
(repeat it for all otehr lvols)
lvreduce -m 0 /dev/vg00/lvol1 /dev/dsk/c1t0d0
vgreduce /dev/vg00 /dev/dsk/c1t0d0

Advantage is that the downtime is minimal. Disadvantage is that the backout is not guaranteed.

Method 2: Create new volume groups and filesystems and copy the data. Follow vgcreation and lvcreation process using the new disk c4t0d0. Create filesystems and copy the data back from the old filesystem. Application/Database is to be down while you copy the data. Unmount old filesystem and vgexport the old volume groups.

Advantage is that you will have good backout plan. It is very safe. Drawback is that it requires extended outage.

5. Disconnect the primary path and connect the other cable and extend the alternate links.

ioscan -f;insf

vgextend vg01 /dev/dsk/c5t0d0

You may be disappointed if you fail, but you are doomed if you don't try
Esteemed Contributor

Re: migration of data from storage work to EMC storage

I don't have tons of SAN experience, so I'll leave those details to someone else, but I will say that I've successfully done online migrations. I typically take the host down to add fibre cards when possible, then the migration can take place at will. Assuming I have space for at least one more PV in the VG, I have the new storage assigned down the new card(s). Then I vgextend a volume group to include new disks, pvmove the extents (I've done it underneath a running Oracle database with no issues several times and have no evidence to suggest it was luck), then vgreduce the old disks out of the VG. Disconnect the old disks at will.

Sorry I can't address the SAN details, but I hope I at least lent support to your idea.

What kind of a name is 'Wolverine'?
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