For instance, software downloads are exclusively reads.
“They won’t notice it so much because they do way more reads than writes.
It needs to get the updated version from the hard disk drive,” Handy said of read-only cache.For, the data is updated later on the hard drive to make sure the original is still updated when the copy is deleted from cache.LSI also has a MirrorCache feature, which prevents the loss of data if it is copied in cache and not yet updated on the hard drive.Handy said read and write caching is faster than read-only caching.“Some applications won’t benefit from read and write caching,” Handy said. “If the processor wants to update the copy, then the copy in cache is invalid. “Hosts can take I/O really fast, but the problem is traditional hard disk drives can’t keep up.”LSI claims the software is the industry’s first SSD technology to offer both via a controller.LSI lets users upgrade a server or array by plugging in a controller card with CacheCade.Īll the I/O traffic is going to the controller.”SSD analyst Jim Handy of Objective Analysis said it took time for LSI to build in the write caching capability because “write cache is phenomenally complicated.”With read-only cache, data changes are copied in the cache and updated on the hard drive at the same time. LSI’s CacheCade partners include Dell, which in May began selling the software with Dell PowerEdge RAID Controller (PERC) H700 and H800 cards.“What we want to do is close the gap between powerful host processors and relatively slow hard disk drives,” said Scott Cleland, LSI’s product marketing manager for the channel. MegaRAID CacheCade Pro 2.0 is priced at $270 and is available to distributors, system integrators and value added resellers. The caching software works on LSI MegaRAID 9260, 92 series of 6 GB SATA and SAS controller cards.LSI delivered the first version of CacheCade software about a year ago with read-only SSD caching.
The software is designed for high-I/O, transaction-based applications such as Web 2.0, email messaging, high-performance computing and financials. LSI MegaRAID CacheCade Pro 2.0 speeds application on hard drives by using SSDs to cache frequently accessed data.
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