LUN migration on EMC CLARiiON

dataminingSince we are upgrading our EMC CLARiiON CX3 to a CX4 this month, EMC has suggested that I get some LUN’s off of the vault (I didn’t put them there) and migrate them to another series of LUN’s. The vault is an array of disks used for storing the system cache – I never liked having other LUN’s on it. So, I am migrating LUN’s off of it, and this is taking some time due to the amount of data. This can be used to move the LUN to a bigger LUN or just to move it for performance reasons. To migrate a LUN is simple:

First, it is required to have some spare LUN’s on a RAID group(s) that are the same size or greater as the source LUN. Right-click on the LUN to migrate (source) and select migrate. A selection of prospective targets LUNs will be displayed. Select the target and the migrate. Very simple. The target will assume the identity (LUN number) of the source LUN when the migration is completed, and this is entirely transparent to the host that is using the LUN and there will be no interruption in LUN access on the host. The migration could take some time depending on the amount of data, of course.

If migrating to a larger LUN, it would be good if the disk were dynamic on the host, if possible. Then, one could just rescan the disks (on Windows Server) and the new larger space would be enabled. If the partition on the host is basic, one would have to use Microsoft Server’s DiskPart – an effective but risky utility.

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