Storage
Disk I/O can be a major bottleneck for CRM, ERP, and other database-oriented enterprise applications. In order to get adequate performance, it may be necessary to spread the data over a large number of drives, but that can prove very expensive if you end up buying much more storage than you need just to get sufficiently fast responses.
An alternative is to use solid-state storage devices such as Platypus Technology’s QikDATA. According to co-founder Geoff O’Reilly, solid-state storage is appropriate when you need fast, genuinely random access to small blocks of data. CRM is “a classic application”, he says, because call duration is normally a primary metric for call centres. Customers ringing in provide randomness, and only a small amount of data involved per transaction.
Either the entire database can reside on solid-state storage, or just the hot files (most frequently accessed data) with the remainder on conventional storage.
“It’s not hard to see a tripling of performance,” says O’Reilly, and some customers have reported a twenty-fold improvement, depending on the nature of the bottleneck, processor power, and other factors.
Solid-state storage looks expensive on paper—a 32GB QikDATA with battery backup and standby hard disks to ensure data is preserved in the event of a power outage costs around $100,000—you would need “100 to 200 spindles” of hard disk storage to get equivalent performance, says O’Reilly.
Energis, a major UK telecommunications and e-business solutions provider, was using 30 e-mail servers to handle 10 million e-mails per day. By replacing conventional storage with a pair of QikDATA units (two were used to provide redundancy, not capacity or performance), four dual-CPU servers were able to do the job of the previous 30, which could then be redeployed elsewhere.
External disk storage units may also offer the option of large amounts of solid-state cache memory. Some systems allow administrators to lock particular files into the cache so the data remains available for very fast access. Any changes are written back to disk in case of an outage. For example, Hitachi Data Systems’ (HDS) Lightning 9980V can be fitted with up to 64GB of cache memory.
Juggling data
Consolidated storage gets around the problem of having too much space attached to one server and not enough on another, but not every organisation is ready to move to a SAN. As an alternative to providing sufficient disk capacity to meet any spikes in demand, BMC Software’s PATROL Suite can be used to automatically move non-critical files from one location to another or begin an archiving operation when free space becomes short. According to channel sales director Terry Crawford-Smith, a mining company is using this capability with its SAP-based system to reduce the risk of system failure, as an outage can stop the movement of ships and trucks at the docks at a cost of $250,000 per hour. In these circumstances, even a 10 percent reduction in outages yields a worthwhile saving, he says.
Quest Software’s LiveReorg is another product that can help make the most of disk space by restructuring Oracle databases with virtually no downtime. One user, a Singapore utility, was able to free up over half a terabyte of previously unusable space, says Martyn Pregnell, managing director for Asia Pacific.
If you do have a SAN, HDS claims its HiCommand software will help you manage it better. Designed to integrate storage systems from different vendors into a single environment, it uses open standards such as SOAP and works with third-party software.
“Under-utilised storage systems can be easily recognised and reallocated to needy areas with the movement of a mouse,” according to a spokesperson for Hitachi. The Device Manager module provides a 10- to 20-fold productivity improvement over existing software, the company claims, while the Tuning Manager monitors and analyses SAN resources from a single screen and forecasts storage requirements.
Installing a SAN can be a big, expensive project, but HDS’s director of marketing for Australia and New Zealand Graeme Gleave says SMEs are easing into SANs. The first step is to separate the storage element of the next server purchase, and buy an external storage unit to be directly attached to the server. This only involves a small price premium, he says. Subsequent servers can also be directly connected to the unit (additional drives will probably be needed). Eventually, SMEs can buy a switch to interconnect everything, allowing for non-disruptive changes in future. At that stage, they should also buy appropriate management software such as HiCommand to make full use of the SAN.
“It’s a planning exercise—you have to sit down with the vendor or the vendor’s partner” to establish a roadmap, says Gleave. In any case, such projects “should be planned well in advance. These are not knee-jerk purchases,” he adds.
A progressive rollout is the strategy adopted by medical device manufacturer ResMed, which started by directly attaching an HDS Thunder 9200 storage unit to an AlphaServer cluster. The second phase saw the purchase of a pair of Brocade 3800 Fibre Channel switches interconnecting the Thunder, the cluster and three Sun servers. The next step will be to add ResMed’s Windows 2000 servers to the SAN, either by Fibre Channel or iSCSI.
Creative financing or leasing arrangements are an alternative to phased implementations as a way of getting a project past short-term financial hurdles, suggests Gleave. A SAN installation may offer a “fabulous” ROI over three years, he says, but if the board requires a measurable benefit from the first quarter the answer may be a smart leasing model that reduces the upfront costs.
