Logical unit number, the slot that identifies each data disk attached to a virtual machine. No two disks on the same VM can share one.
Also called logical unit number.
In the Ultra Transcenders books
Each book explains LUN in context, with comparison tables and the common traps.
Terms in this definition
- Data disk
A managed disk for application data, connected to the VM at a specific LUN. Attaching it while the VM is running causes no downtime.
- VM
A computer implemented entirely in software, having virtual hardware and its own guest OS; ESX hosts run it and vCenter manages it.
- Share
In OpenSharing, the container you fill with tables, views, volumes, models and notebooks for recipients. You need
CREATE SHAREon the metastore to make one; add a schema and all its assets, including later ones, go with history.
Related terms
- copyIndex()
Returns the current iteration of an ARM copy loop, counting from zero; inside a property loop, give it the loop name, as in
copyIndex('dataDisks'), so every disk gets its own LUN and name. - MPIO
Multipath I/O: a Windows Server feature that reaches the same SAN LUN over more than one physical route, such as several HBAs or iSCSI sessions, to provide failover and spread load, via the Microsoft DSM or one supplied by the storage vendor.
- Thin provisioning
Giving a virtual disk or LUN space only when data is actually written, so it can appear bigger than what it currently consumes. Fixed provisioning, in contrast, reserves the full size up front.