Storage Management Strategies for the CIO
This article can also be found in the Premium Editorial Download "Storage magazine: Backup overhaul: From a mainframe to an open-systems environment."
Download it now to read this article plus other related content.
New server-to-storage host bus adapters offer significant performance gains, but there are some pitfalls to avoid.
Out with the old, in with the new: Serial-attached SCSI (SAS) and iSCSI host bus adapters (HBAs) are the new vanguard in server-to-storage connectivity. SAS HBAs are poised to replace parallel SCSI HBAs, while iSCSI HBAs offer companies the option to use an Ethernet storage network in lieu of a more costly Fibre Channel (FC) SAN for all of their servers.
Of course, SAS and iSCSI HBAs address different corporate storage connectivity needs. SAS HBAs help eliminate storage I/O throughput bottlenecks to internal or direct-attached storage (DAS) while expanding the number of storage devices a single server can address to more than 16,000. iSCSI HBAs open the door for organizations to connect high-performance servers to their Ethernet storage network.
A single SAS HBA card such as LSI Logic Corp.'s LSISAS3080X-R contains eight separate ports for I/O. Each port can operate at 3Gb/sec at half duplex and can concurrently communicate with both SAS and SATA hard drives. New iSCSI cards, such as Alacritech Inc.'s SES2100 and QLogic Corp.'s QLA4050C, improve TCP/IP offloading by separating the overhead from the server's CPU, which helps Ethernet networks meet the stringent I/O and throughput requirements of high-performance servers.
But despite these benefits, new iSCSI and SAS HBAs have their downsides. For example, SAS HBAs don't
Requires Free Membership to View
offer N_Port ID Virtualization (NPIV); as a result, a storage administrator must use one SAS HBA worldwide name per server. And if you need to reuse existing network-attached SCSI or FC storage devices with new iSCSI or SAS HBAs, you'll need a bridge or router for the SAS or iSCSI HBA to communicate with those legacy storage devices.
This was first published in April 2007
Join the conversationComment
Share
Comments
Results
Contribute to the conversation