Hierarchical storage management from a mirrored file system on a storage network segmented by a bridge

DETAILED DESCRIPTION A solution to this problem is provided according to the teachings of the invention by mirroring the data over a Bridge.
The Bridge segments the FC-AL into two FC-ALs or two LANs of any other type.
One of these LANs carries high speed, high data availability online transaction processing traffic between a Transaction Server and a primary memory, typically comprised of a high performance JBOD or other high speed storage devices.
This first LAN or local area network will hereafter be called the Primary Loop or primary FC-AL.
The second LAN or FC-AL will be called the Secondary Loop or secondary FC-AL.
It carries hierarchical storage management (hereafter HSM) traffic between an HSM backup server and a mirrored memory, typically also a high performance JBOD or other high speed storage device.
The Secondary Loop also carries data between the mirrored memory and backup/archival storage devices such as tape drives or WORM drives.
The Primary Loop and Secondary Loop referred to herein are preferably FC-AL, but they may be any other type of local area network such as Ethernet, fast Ethernet, ATM etc.
The way this system works is as follows.
For any write transaction from a high speed transaction processor to a high performance JBOD over the Primary Loop, an additional write operation is carried out over the Bridge and the Secondary Loop to the mirrored-storage HSM disk drives.
The write transaction to the mirrored disk drive device or devices on the Secondary Loop so as to mirror the data stored on the disk drives in the Primary Loop does not slow down processing on the Primary Loop because of the presence of the Bridge.
If the Bridge were not present, a write transaction to a backup storage device such as a mirrored backup disk drive stalls all further transactions with the fast storage devices in the Primary Loop until the transaction with the backup storage device is completed.
However, the mirrored disk drives are fast devices so write transactions to them are very fast even though the data must traverse the Bridge