The CSL SAN (Storage Area Network) is a redundant cluster providing iSCSI and NFS storage to other servers. Its primary purposes is to provide iSCSI storage for VM hard drives.
Snares and Bottom each have an LSI PCI-E dual-port SAS-2 HBA. They are connected via copper SFF-8088 cables to Apocalypse such that each server has access to all of the drives in Apocalypse. Any Server, HBA, or backplane component within Apocalypse can fail without a loss of functionality.
A number of pieces of software are used on top of the SAN hardware to provide data mangement and redundancy, high availability, and iSCSI and NFS access.
ZFS via the ZFS on Linux project is used as the filesystem on the SAN. Currently there is a single zpool, called apocalypse, with 10 drives in a RAID-Z2 and an eleventh drive as an online spare.