Moving DAE to different bus without dataloss?

Question

Is it possible to move a DAE to a different bus on a CX500 without having to recreate the LUNs on those disks? We'd like to balance things out a bit different and have it match our other CX500 configuration, and I'm hoping the array can just see that these disks/LUNs moved to another bus.

DGM3 · Accepted Answer

The array will not bring online a RAID Group and its LUNs if they are relocated to a different backend address (different bus number and/or enclosure address). The array cross-checks "where bound" information with current topology to ensure any LUNs brought online are consistent with previously known topology. I realize this is not what you hoped to hear, but wanted at least to avoid you spending time on the effort.

Regards,
DGM

EKellerman · Answer

I have a feeling the answer is no, but I'm not sure. I would think the array would fault when you removed the DAE from the bus and present all the disks in the DAE as missing. After you moved it, it would probably present it as a new DAE with fresh disk.

I'm guessing though, so someone else may have a definite answer....

Other options:
Do you have the capacity to copy LUNS using the Migrate function (if your FLARE is high enough)? Or do you run any backup/recovery software ie, SnapView, SanCopy?
Another option would be to create new luns and present them to the host, then use a host based utility to copy over, and finally cutover to the new luns.

BPickering1 · Answer

I was pretty sure it wouldn't work if the array is up(even with I/O stopped on that LUN), but we were planning on doing it during some downtime and have everything shutdown. My hope is that it just scans the disks at bootup to find the LUNs and doesn't really care what Bus or Enclosure they're in, similar to the way LVM and MD works in Linux.

Unfortunately we don't have any spare room for a LUN this size (3.2TB), though it is just a MirrorView destination and can be rebuilt from the primary if I need to destroy it to move. I'm just hoping to avoid that ~36hr rebuild time.

BPickering1 · Answer

Oh well, thanks for the information.I guess we'll just delete and recreate the LUN and let it mirror up.

CLARiiON

Moving DAE to different bus without dataloss?

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