Migrating a virtual machine that uses 100% virtual disks is a simple task due to VMware Storage vMotion but migrating a VM that uses Raw Device Mappings from one array to another is somewhat trickier. There are options to convert a RDM into a virtual disk but that might not be feasible for applications that still require RDMs to be supported. Other options are host based mechanisms/in-guest mechanisms to copy the data from one device to another. That option sometimes can be complex and requires special drivers or even possibly downtime to fully finish the transition. To solve this issue for physical hosts, EMC introduced for the Symmetrix a feature called Federated Live Migration.
Federated Live Migration (FLM) allows the migration of a device from one Symmetrix array to another Symmetrix array without any downtime to the host and also does not affect the SCSI inquiry information of the original source device. Therefore, even though the device is now residing on a completely different Symmetrix array the host is none the wiser. FLM leverages Open Replicator functionality to migrate the data so it has some SAN requirements–the source array must be zoned to the target array. A FLM setup looks like the image below:
Continue reading “Migrating a Raw Device Mapping with Federated Live Migration”
First post! As I am fooling around with the templates and colors and such and getting used to blogging I figured I would kick things off with something simple and one of my favorite unheralded new features of Solutions Enabler (SYMCLI) 7.6 that was released at EMC World 2013: “quick meta creation”.
****UPDATE: Apparently this was enabled long before SE 7.6, SE 7.3 at least actually, so you probably already have this feature, thanks to Jason Moreland for pointing this out****
As anyone familiar with the VMAX is most likely aware Symmetrix logical devices have a size limit of 240 GB. And in most virtual environments the size of clustered file systems that are desired, such as VMFS, usually need to be much bigger than that. So the solution on the VMAX array is to create what we call a metavolume (which I will refer to as a meta henceforth because I am a lazy typist). This is a simple logical association of multiple VMAX devices and are manipulated to look like one larger device which allows the size of a device as seen by the host to be VERY large (255 total members possible x 240 GB size each–you do the math). These devices can be “connected” together either via concatenation or via striping.
Well of course this is old news, why is this the least bit interesting?
Continue reading “First post and a quick SYMCLI shortcut”