SuperSyncTM Disk Array
for Stratus VOS V Series
Protect your data in the event of a drive failure even while running simplexed during a rebuild!
SuperSync Disk Array
The SuperSync Disk Array was designed to emulate a tray of VOS disks with no user intervention or configuration required. Once the SuperSync Disk Array is connected to the Stratus host and powered up, the disks are set up, initialized, and mounted with the exact commands as standard VOS disks.
Even with duplexing, when using standard magnetic drives, data will be lost if a second failure occurs before the replacement drive is restored to service. When disks were small and rebuild times were short susceptibility to a second disk failure may have been acceptable. However, as disk drives have grown larger and larger, the window of exposure to a catastrophic data loss has greatly increased. During a rebuild, if the surviving drive fails gigabytes of critical data will be lost. A 34 or 36 Gigabyte disk could take a day or longer to resynchronize after the new disk is powered on.
This is not so with SuperSync. SuperSync Disk Arrays provide parity protection even when running simplexed during a rebuild. SuperSync will continue processing data even if a disk is lost. Therefore, no data will be lost.
The SuperSync connects directly into a Stratus VOS V Series via the U528 or JBOD port as shown here:
The Stratus host sees the SuperSync as one or more standard VOS disks.
The SuperSync back panel connections include dual fiber connections for host data transfer, dual Ethernet connections for support hub and network access, and dual power connections.
The SuperSync is shipped from DRA in a fully configured, pre-tested, un-initialized, and ready-to-run condition. Normally there is no need to change any internal settings on the SuperSync.
SuperSync’s physical and logical configurations are shown here:
SuperSync stores data on one or more virtual VOS disk types. The virtual disk types match so exactly the equivalent physical disk type that a virtual disk can be duplexed with an equivalent physical disk. VOS D913 and D914 disks are currently supported on SuperSyncs. Stratus no longer sells D913 disks, but the D913 disk type remains in VOS. Therefore, SuperSyncs can be configured as D913s. If SuperSyncs are partnered to SuperSyncs or StorGates, users may choose to use the D913 disk type, depending on their capacity needs. However, for most users it will no longer be practical to partner SuperSyncs to Stratus D913 disks.
SuperSync Disk Arrays provide internal redundancy. The SuperSync is configured with a parity drive. If one drive fails, the others keep running. No data or processing time is lost.
When a VOS application issues an I/O request, the VOS I/O subsystem converts it to a physical I/O command. The U528 then passes this command to SuperSync over the Stratus fiber port.
SuperSync responds to each VOS physical I/O command exactly as a standard VOS disk would respond. In order to accomplish this disk emulation, SuperSync converts the Stratus disk address into an address for the corresponding data on the target, performs the appropriate I/O operations on the target, then converts data and status returned by the target into an appropriate response for the U528.
Internally available OS features allow DRA to support SuperSync via remote dial-in connections. Parts are easily replaced and drive bays are hot pluggable. Internal power supplies are redundant.
DRA products purchased directly from DRA are supported through the Co-active Maintenance Service (CMS). CMS is a total support agreement which is available "around the clock, around the world" to participating DRA customers. Product maintenance, product updates, documentation and training are available through CMS support. CMS is provided free of charge for 90 days following product installation, and may be extended by contract thereafter.
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