Recent IP storage growth has been impressive. According to IDC, there were 32,124 terabytes (TB) of iSCSI storage...
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deployed worldwide in 2005. That figure had almost tripled to 97,506 TB by 2006. Users are quickly adopting IP storage for its low complexity and deployment costs. Some organizations are using IP storage as an alternative to scattered storage technologies that often proliferate and cause management headaches such as NAS and DAS. The ubiquitous nature of IP networking also positions IP storage (a.k.a. iSCSI) networks as an ideal medium for remote backup and disaster recovery tasks.
IDC expects almost 4 million TB of iSCSI storage to be deployed by 2010. "We continue to believe that IP-based storage will be a significant area of focus for vendors in 2007," says Brad Nisbet, program manager for storage systems at IDC. But IP storage adoption has been far more than just a numbers game. ISCSI has been making real inroads in both small companies and large enterprises.
Positioning for low costs and rapid expansion
The move to IP storage was not immediate. TNCI wanted more flexibility and expansion capacity in the storage hardware, but the costs of Fibre Channel components and switching needed to connect numerous servers to the storage area network (SAN) made Fibre Channel expansion prohibitive. "With Fibre, we found the average cost of connectivity to be about $2,000 [per server] just thinking about Fibre HBAs in those servers," DiBenedetto says, noting that the same server can be connected to an IP SAN for around $750. "Cost for connectivity was a major factor in choosing IP storage."
It took TNCI almost a year to decide on iSCSI, which included a great deal of research and hands-on testing. One pivotal factor in its choice of iSCSI involved its important VMware Inc. ESX server -- only recently upgraded to support iSCSI. TNCI finally settled on two EqualLogic Inc. IP SAN arrays; the PS300 with 7 TB (about 5 TB configured) and the PS100E with 3.5 TB (about 2.25 TB configured). DiBenedetto points out that the EqualLogic iSCSI arrays can scale very easily, pushing well beyond the 8 TB limit of the MSA1000. Today, iSCSI handles the entire production environment for TNCI, including Exchange, SQL databases and user data. "Anything production based is running off that iSCSI SAN," he says. The older storage systems have been relegated to storage archiving and test purposes.
There have been significant savings in the eight months since the introduction of IP storage. "In that timeframe, we've probably saved $15,000 just in connectivity costs," DiBenedetto says. Savings of 25% to 30% are also expected in ongoing storage costs as the iSCSI storage systems are scaled up into the future. Savings are enhanced even further with better storage utilization, which DiBenedetto expects to approach 100%. Still, the adoption of IP storage has its issues. DiBenedetto recommends that you certify your critical applications for iSCSI before moving them to IP storage and take the steps to segment and secure the IP storage traffic to avoid bottlenecks in the production IP network.
Interestingly, the performance of IP storage seemed at least as good as Fibre Channel -- a point that DiBenedetto attributes to disk utilization. "They're spreading the volumes across larger numbers of disks -- more spindles," he says. "They're using lots of SATA or SAS disks to increase performance."
Positioning for backup and disaster recovery
A steel manufacturing giant might seem like an unlikely place for IP SANs, but Mittal Steel USA was struggling to protect 10 TB in DAS. Not only had backup and disaster recovery tasks emerged as serious concerns, but Mittal also needed to centralize its storage, improve storage management and ease upgrade disruptions, and find a means to support storage-hungry tasks, including disk-to-disk backups, SQL databases and Microsoft Exchange.
SAN adoption was inevitable, but the choice between Fibre Channel and IP storage demanded a careful consideration of Mittal's budget, technology, IT skill set, ease-of-use, expandability and detailed discussions with other users of both technologies. During an email interview, W. Dean Sheets, IT demand manager at Mittal, said IP SAN technology met all of the organization's objectives -- and actually resulted in multiple iSCSI SAN deployments. "We deployed the [iSCSI] SANs at three locations; one at the primary U.S. data center, one at the local area disaster recovery location and the other at a wide area DR location." The main U.S. data center now handles 32 TB using eight arrays in a RAID-50 configuration and one array set up for RAID-10. A local disaster recovery facility supports almost 10 TB with two arrays in a RAID-5 configuration. The U.S. disaster recovery data center handles 11 TB with two RAID-50 arrays and one RAID-10 array.
Although Sheets declined to specify Mittal's iSCSI products, he was clear that the move to IP storage SANs fully addressed Mittal's performance needs. "[We] met our need for wide area SAN replication within our WAN speed constraints," he says. "[This let us] fulfill our plan for disk-to-disk-to-tape (D2D2T) backup -- hundreds of servers do their backups to the SANs, which are eventually put on tape. This allowed us to stay within backup time windows." Sheets also pointed to the ease of Web-based management, simplified hardware and potential to implement virtualization at some point in the future.
Sheets notes that practical issues, like optimum NIC selection, switch port configurations and the choice of RAID levels (particularly RAID-10) surfaced during the deployment process. Still, he reports that its IP SAN deployment went smoothly overall, and the results were intriguing. "We actually saw great improvements in performance on all applications compared with our legacy direct attached storage," he says. "This was most noticeable on file servers." Mittal currently has several IP storage upgrade projects that are awaiting approval.
Moving to consolidation
It was obvious early on that the centralization and sharing of a SAN would be essential before CHLA could ever manage its storage effectively. Ferber spent over a year researching SANs for the hospital. "Fibre Channel presented a lot of challenges that frankly I didn't want to afford," he said. "And how much performance do you really need?" Storage performance had been terrible because the storage devices were full, so Ferber concluded that adequate results could be realized without the expense and overhead of Fibre Channel -- a decision that eventually led to the deployment of two LeftHand Networks Inc. IP storage SANs connected by an optical fiber link. Ferber reports that the initial installation was problem free and took about three days.
Today, 19 TB is currently deployed in IP storage (that figure is expected to double in 2007) and iSCSI storage has totally replaced the decentralized DAS architecture; bringing cost and management savings to the enterprise. "I know I save 40% of what a Fibre Channel [SAN] would have cost," Ferber says. "I showed a return on investment in less than a year." Additional iSCSI storage can automatically configure and grow volumes as needed, simplifying the management needs for IP storage. As more users embrace centralized SAN storage, Ferber is systematically removing Zip drives and other decentralized storage devices.
The next big push for CHLA's storage infrastructure is to eventually eliminate tapes. Although tape use has declined with the adoption of IP storage, it is still an essential part of long-term data retention for children's medical records (currently 21 years). Still, Ferber expects tape use to fall up to 90% as RAID and disk-to-disk backup become more prominent.
The enterprise is noticing
IP storage was considered to be a low-end technology only a few short years ago -- a simple answer to shared storage in the SMB. But it's clear that IP storage, in the form of iSCSI, has captured the attention of larger organizations. Ultimately, traditional FC SAN deployments are expensive to deploy, cumbersome to configure, and difficult to expand. Conversely, independent NAS and DAS deployments can easily become impossible to manage and protect. Users see iSCSI as a cheaper and easier SAN technology that can grow rapidly while still providing solid storage performance for users. IP storage is also proving itself in high-end tasks like backups, remote replication, snapshots and RAID. Although it's still not the predominant choice for transaction-centric data centers, IP storage is finally taking its place as an important storage technology in the enterprise. ***