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ShaoLin InfiniCluster Cluster requires a reliable shared storage device to act as a shared storage for the clusters. In the event of hardware failure, it is desirable to be able to disconnect one cluster member from the shared storage for repair without disrupting the other cluster. Shared storage is truly vital to the cluster configuration
The following storage types are supported by ShaoLin InfiniCluster Cluster.
Just a Bunch of Disk (JBOD)
This refers to disk arrays that is just a bunch of disk. JBOD storage does not come with any redundancy, you have to use Linux software RAID (MD) to provide on-line redundancy. ShaoLin InfiniCluster Cluster supports software RAID, you may refer to your Linux distribution for more information on setting up software RAID during OS installation. Or you may refer to the document Software RAID HOWTO on information setting up software RAID in Linux.
RAID subsystem and storage enclosure
This type of disk array have RAID controllers built-in, and emulate as a normal SCSI device which works independent of the operating systems and does not require special drivers.
Host Adapter RAID This refers to using host bus adapters that has RAID controller built-in, and connect to a JBOD storage disk array. Not all host adapter RAID supports cluster configuration
ShaoLin InfiniCluster Cluster uses the shared storage as a startup drive for the clusters. It is required the shared storage is bootable from the clusters simultaneously. Most of the SCSI and fibre-channel shared storage devices are bootable, it depends on your host adapter settings. Please consult your hardware vendor for detail configuration of your SCSI or fibre-channel host adapter for bootable configurations.
Other considerations which not limited to ShaoLin InfiniCluster Cluster is the configuration of disk arrays. It is highly recommended to use RAID-1 or RAID-5 in your disk array for redundancy and no single point of failure. Do not use RAID-0 which doesn't have any redundancy features. ShaoLin InfiniCluster Cluster supports both hardware RAID and software RAID which provided by the Linux MD driver. The best selection would be using hardware RAID enclosure disk array boxes , in which the RAID controller is built into the disk array subsystem. Other host adapter hardware RAID is also supported by setting the host adapter RAID to use write through cache scheme. Using write back cache scheme will cause data lost in case your host adapter malfunction or disconnection of the failed cluster with pending buffers in the adapter cache. However, not all host bus adapter RAID is capable to run in a cluster configuration. Please ask your product vendor for information on using the host adapter RAID in a cluster configuration
FC and SAN virtualized storage also have benefits from storage management. By using appropriate SAN management software, such as the IBM SAN Manager, you can configure multiple cluster pairs to share on a single storage pool. This also ensure storage consolidation and maximum utilization in management point of view. If budget is available, it is highly recommended to use SAN storage which benefits from future expansion and easy management.