After finding that even a hybrid flash array failed to prevent its most important application from slowing to a crawl during activity spikes, Riverview Hospital switched to an all solid-state array to reduce latency and handle writes faster.
Riverview Hospital is a full-service county hospital in Noblesville, Ind., with 154 beds, 20 off-site facilities and nearly 1,200 employees.
Early this year, the hospital switched to an 11 TB Pure Storage FlashArray to increase the IOPS available for a few critical applications, mainly its Allscripts Healthcare Solutions Inc.'s Pro electronic healthcare records (EHR) system, a 550-seat VMware Inc. View 4.6 virtual desktop infrastructure (VDI) deployment, and Citrix Systems Inc. XenApp virtual servers.
The EHR application server is a 1.5 TB virtual machine that runs a Microsoft SQL database. More than 300 doctors at the hospital use the EHR app. Jason Pearce, Riverview's enterprise architect, calls it the hospital's most important application.
Pearce said he installed the Pure Storage FlashArray after his IBM Corp. Storwize V7000 virtualized hybrid storage system struggled during activity spikes, which caused unacceptable delays to 250 persistent virtual desktops and the EHR app.
"It got to be where the latencies were becoming more regular and more noticeable by the end users, and I needed to make sure I found a way to minimize those latencies," Pearce said.
The IBM V7000 had a mixture of solid-state drives (SSDs) and spinning disks. Pearce said it handled data reads well because it could cache that data in the SSDs. But the V7000 could not keep up on writes and access to the virtual desktops and the EHR SQL Server database suffered.
Pearce investigated a number of solid-state alternatives, but found that few were willing to do an on-site proof of concept. He tested Fusion-io Inc.'s ioDrive solid-state PCI Express (PCIe) server cards in his VMware Inc. ESX hosts. He said the server flash provided "wicked fast reads," but didn't solve his write problem. Performance monitoring tools told him the Fusion-io cards were helping, but he received the same calls from frustrated Allscripts EHR users.
Pearce visited Pure Storage at VMworld in San Francisco last year. He saw a demonstration at the booth, and Pure agreed to an on-site, proof-of-concept deployment. He said installation was quick, and "within an hour, we were mapping LUNs and getting vCenter set-up."
He started testing by putting virtual XenApp servers on the solid-state array. Then he added VMware View temporary virtual desktop pools and ran into an issue. The array hung for about 20 seconds, which caused all the virtual desktops to lose their connections.
But Pure Storage's customer service team found and fixed the problem.
"I would say that while that was a bit of a loss of confidence early on, they seriously addressed the problem, worked to find answers, kept me posted, and really did a bang-up job," Pearce said.
It turned out that his older View 4.6 virtual desktop platform and his newer VMware vCenter management software handled SCSI reservations differently, which caused the 20-second delay.
The weekend after fixing the SCSI bug and getting the array up and running, he encountered another issue that caused a shorter service disruption. This time, Pure Storage called him within 10 minutes of the disruption before he could even log on to his system and see what the issue was.
Cost-effective solid-state storage
Pearce expected great performance out of the solid-state array, but he said he was surprised by the data reduction benefits since moving his SQL Server database and VDI deployment onto the system. Pearce said that his 1.5 TB SQL Server database became a 200 GB database once the Pure Storage FlashArray ran it through its data deduplication and compression algorithms.
He also found great benefits to deduping his VDI environment. "VMware View is nothing but [duplicate data]," Pearce said. "It's just clone machine after clone machine. I get 550 desktops in just a couple hundred gigs. They are all Windows 7 [desktops]; it's very standardized."
Pearce said he has the two SQL Server databases, his VDI environment and eight Citrix XenApp virtual servers running on the Pure Storage FlashArray, and he's only at 9% of his total capacity. His overall data reduction ratio is just above 7-1 and his combined read-and-write latency is around .4 milliseconds.
Pearce said his next project will be to identify applications on the IBM V7000 hybrid array that demand the most IOPS, and move them to the Pure Storage array.