With data growth showing no signs of stopping and budgets shrinking everywhere, users are coming up with creative...
ways to avoid expensive storage expansions, while maintaining existing service levels. One IT pro found the way to do that is by boosting throughput on the server side of the network with a TCP/IP offload engine (TOE) card from Alacritech Inc., while maintaining the same storage systems.
Jason Warzinik, GIS program manager for Boone County, Mo., had been maintaining a total of four Cybernetics iSCSI miSANs, two dedicated to the GIS system and two connected to servers using Adaptec Inc.'s now-discontinued 7211C iSCSI host bus adapter (HBA). "We did that for redundancy purposes since the HBAs were single-ported," Warzinik said. Having two SANs and two HBAs provided a dual path.
But about three weeks ago, the county launched its first full-color satellite GIS maps of the county, which boosted the size of each map file that would be delivered through the county's Web portal from around 43 GB to around 300 GB. In preparation for that project, Warzinik re-evaluated his storage environment.
Another option was to see if a different kind of iSCSI initiator might boost performance. Warzinik tested Alacritech's SES2002XT TOE card against Adaptec's HBA in IOmeter, using 256 KB blocks and a dual Xeon 3.4 processor. The Alacritech TOE card gave him a throughput of 63 MBps for reads and 46 MBps for writes, compared with the 7211C HBA's 33 MBps and 29 MBps, respectively. It also performed with an average I/O response time of 3 msec on reads and 5 msec on writes, compared with the HBA's 7 msec and 8 msec times.
Unlike an HBA, a TOE card adds an accelerated network interface card (NIC) to the one already used for Ethernet traffic on the server, offloading the processing of the TCP/IP protocol used with iSCSI storage from the server's main CPU to its own. (Some iSCSI HBAs, such as those from QLogic, also include TOEs.)
TOE cards have fallen out of favor in recent years as server processors caught up to the task of processing Gigabit Ethernet. However, some observers predict TOE cards will be back as 10 Gigabit Ethernet network capacity leapfrogs processing power again. Alacritech's OEM partners are evaluating its 10-GigE TOE cards, and direct of product managment Patrick Riley said he expects the cards to launch later this year.
For Warzinik, the Alacritech GigE card not only boosted performance, it also eliminated the need for dual SANs for redundancy, since it came with dual ports. "That allowed us to repurpose our other SAN for GIS work files in addition to avoiding the purchase of a third $8,000 array," he said.
Today, Windows files are served from the miSAN to the county's Web portal through the Alacritech TOE card. While Warzinik said he's satisfied with the support he's gotten so far, Alacritech's TOE currently only supports Windows, and the GIS work files stored on the repurposed miSAN are under a Novell NetWare server. "Unfortunately, Alacritech doesn't help us there," but the most critical performance needs are on the server feeding the website, he said.
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