PathGuard for MPIO
PathGuard overview
PathGuard builds multiple I/O paths from a host computer to virtual disks in Arena RAID systems. I/O can be dynamically distributed over the paths so as to utilize all possible bandwidth, and the multiple physical paths are presented to operating system as a single high-performance logical path. PathGuard offers selective load balancing mode for users to match different performance requirements. When an I/O path is down, like loosed cable or a failed HBA port, PathGuard will redirect I/O from the faulty path to the other healthy paths. And when the faulty path is recovered, PathGuard will automatically utilize the recovered path.
PathGuard enhances performance
With PathGuard, a virtual disk can serve I/O concurrently via multiple paths, and it thus eliminates the limitation that the maximum data transfer rate of a logical disk is bound by the maximum data transfer rate of single I/O path. In addition, without PathGuard, physical paths need to be statically assigned to virtual disks, and as a result, the bandwidth of all paths cannot be fully utilized if the loading on different virtual disks is uneven. Because PathGuard transfers data over all workable paths, the utilization of path bandwidth as well as the ROI (Return-On-Investment) can be largely improved.
PathGuard improves system availability
PathGuard protects system availability against path failures. The failure of single path will not result in discontinuity of the system operations, and the applications can continue to access the storage devices without being aware of the path failures. PathGuard keeps monitoring the status of all paths and informs users of any status change. All events regarding to paths are also recorded to the system log for history tracking. All the path management tasks are done by the PathGuard web-based GUI.
PathGuard simplifies management
PathGuard can simplify the path management and storage presentation operations. With the dynamic load balancing offered by PathGuard, users need not to worry about either bandwidth planning during the deployment or the reconfiguration for performance tuning. When there are new HBAs or new connections added, the bandwidth created can be utilized easily by adding the new path to the PathGuard. Together with the Symmetric Storage Presentation (SSP) feature offered by the Arena RAID systems firmware, users can export storage resources easily by mapping the logical disks to the host computer caring nothing about which paths to be used.
PathGuard outperforms host-based software striping (RAID 0)
Similar to PathGuard, host-based software RAID utilizes multiple paths to serve I/O for single logical drive on a host system. However, there are some significant differences between the two approaches. First, although both PathGuard and software RAID offer performance improvements, but only PathGuard can tolerate path failures. Secondly, software RAID forces I/O to be truncated into data stripes, which results in unnecessary overhead and limited size of data transfer in single I/O (for example, the data transfer size of single I/O in Windows software RAID is up to only 64KB). And finally, software RAID stores RAID configurations on the data area, which can be accessed by malicious applications, and user data will be completely gone if the RAID configurations are corrupted.
PathGuard Download:
Support Model: SA-4551S, SA-6651S, SA-6651E, SA-8850S, SS-4551E, SS-4552E, SS-6651E, SS-6652E, SS-6601R, SS-6602R, SS-8801R, SS-8802R
Windows 32bit(v1.13) : Window 2003, 2003R2, 2008
Windows 64bit(v1.13) : Window 2003, 2003R2, 2008
Linux 32bit/64bit(v1.00) : RHEL5, SuSe10, RHEL5-64bitXen
Support Model: SA-6641D, SA-6640S, SA-6641S, SA-4540S, SA-4541S, SA-4340S, SA-4341S
Windows 32bit(v1.4) : Window 2000, 2003, 2008